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What are the classification of cold drawn square steel

What are the production classifications of cold drawn square steel? According to Xiao Bian's understanding, I will share with you the reasons for the scarring on the surface of 45 ° round steel. The production classification of cold drawn square steel can be divided into production process classification, 16Mn round steel material classification, production standard classification, 42CrMo round steel-40cr round steel-45 ° round steel cold drawn square steel profiled steel section shape classification, and surface treatment classification, However, the impact toughness of 16Mn round steel is very good. Each classification of 16Mn round steel has its own characteristics. The classification of production process and section shape is more detailed, and its performance is not the same. First of all, its plastic deformation is not affected by the appearance of the point, the hardness is many times, making the material hardness. Industrial products, each will appear fatigue and other load parts, in the metal static load under the effect of mechanical fatigue is more increased, but its impact toughness is very good, the impact load ability is more and more strong, make its metal material strength stronger performance. Cold drawn square steel is a kind of product with smooth and bright surface. It can save steel, improve yield strength and save a lot of materials. Cold drawing process is to achieve the required shape, specification and tolerance of raw materials by cold deformation. The consumption of raw materials of stainless steel square steel is very small, and round steel strictly controls the quality. Compared with the materials consumed by traditional lathe machining, the material saved by cold drawing square steel is very considerable, especially when the material consumption is large, the material cost saving is more significant.

At the same time, the cold drawn square steel can greatly improve the processing efficiency and save working hours. 42CrMo round steel - 40Cr round steel - 45 ᦇ round steel - cold drawn square steel - profiled steel - and the accuracy of processing machinery can ensure the surface quality of products. In general, cold drawn steel products can be used directly, such as spraying, sanding, bending, stainless steel square steel drilling, or direct electroplating after fine drawing according to actual requirements, which saves a lot of machining time and the cost of configuring processing machinery.

Cold drawn square steel can be used in different fields, such as various mechanical equipment: woodworking machinery, round steel, strict quality control, ceramic machinery, paper machinery, glass machinery, food machinery, stainless steel square steel, construction machinery, plastic machinery, textile machinery, Jack, hydraulic press, etc; It can also be used for electrical parts, such as motor shaft, fan shaft, sewing machine shaft, etc. Most of the cold drawn square steel is also in the natural environment at room temperature, so that the original steel raw materials can be advanced into the relevant mold shell sample plates that have been produced and processed well, and the production and processing can be carried out according to the technical nature of hot forging. In that case, they will have a series of reflection in the whole process of concrete reflection, In the original fixed building steel yield limit to carry out the compressive strength of fixed, and then let the cold-drawn square steel to carry out the relevant appearance drawing, then all the cold-drawn square steel will have the relevant plastic deformation, can achieve a kind of compressive strength, gradually can also save raw materials.

There are many advantages of cold drawn square steel. In the whole process of design, they can not only design different kinds of molds, but also cold wash their faces. They also have some other cold drawn steel of different specifications. However, their perspective can be set reasonably according to the specific situation, And the precision of cold drawn square steel products is high, because it uses high-quality hard alloy mold shell, and has technical maintenance personnel, so it can ensure the accuracy of all dimensional tolerances.

From the perspective of name, there is only one word difference between cold drawn square steel and cold drawn square steel, but in fact the difference between them is far more than that. Want to know if you are interested in mastering a lot.

Cold drawn square steel is defined as steel with total width of 12-300 mm, thickness of 4-60 mm, rectangular section and slightly pure edge. It can be used not only as finished steel, but also as blank of welded steel pipe and cold rolling of sheet metal. Cold drawn square steel is an auxiliary material aluminum profile, which is mainly used in shipbuilding industry and bridge construction industry.

With the rapid development of shipbuilding industry, the demand for cold drawn square steel is increasing. However, only when designing large and medium-sized ships and basic ships, the galvanized flat steel for ships will be selected for the main hull, and the galvanized flat steel with the same thickness and raw material as the connecting plate will be used as the skeleton raw material to ensure the production quality of ships. What are the advantages and disadvantages of cold drawn square steel?

Advantages of cold drawn square steel: it can cast ingot, refine steel grain, and eliminate micro defects, so as to make steel dense and improve mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel is no longer isotropic to a certain extent; Bubbles, cracks and porosity formed during pouring can also be welded under high temperature and pressure.

Disadvantages of cold drawn square steel:

After hot rolling, the non-metallic inclusions (mainly sulfides and oxides, as well as silicates) in the steel are pressed into thin sheets, resulting in delamination (sandwich) phenomenon. Delamination can deteriorate the tensile properties of the steel along the thickness direction, and interlayer may appear when the weld shrinks. The local strain induced by weld shrinkage is often several times of the yield point strain, which is much larger than the strain induced by load;

Residual stress caused by uneven cooling. The residual stress is the internal self equilibrium stress without external force. All kinds of hot-rolled section steel have this kind of residual stress. The larger the section size of general section steel is, the larger the residual stress is. Although the residual stress is self-equilibrium, it has certain influence on the performance of steel members under external force. Such as deformation, stability, anti fatigue and other aspects may have adverse effects. The basic characteristics of cold drawn square steel and the purpose of surface oil film solution

Cold drawn square steel has long become the main material for light steel structure, which is made of thick steel plate or strip steel; In addition to a variety of building structures, it is also widely used in car manufacturing, agricultural machinery manufacturing and other aspects. Cold drawn square steel is often used in this way. The basic characteristics of products between the two are as follows

It's closely related.

There are many kinds of cold drawn square steel products in different ways, specifications and models. We can carry out relative cold drawn production according to different requirements, so that we can achieve all kinds of production requirements. When it carries out cold drawing skills processing, its production skills are refined, errors and omissions are small, and the degree is high.

For cold drawn square steel products with cold drawing skills, its surface is smooth and its quality skills are exquisite. And the cold drawing process is to achieve the required appearance, specification and size tolerance of cold drawing forming of raw materials, and the consumption of raw materials is very small. This relative to the traditional machine tool processing, of course, more saving natural materials, greatly saving the cost of production.

In the case of engineering acceptance of cold drawn square steel products presented by the manufacturer, we will find that there is a layer of oil slick on the surface of raw materials. For this matter, we must explain that the layer of oil slick on the surface of cold drawn square steel is actually an antirust agent, because the antirust agent is color, so the plate is not easy to look too bright and new.

Generally speaking, the processing ability of semi-finished products of cold-drawn square steel just out of the cold-drawn production line is relatively poor. In addition, the air contains environmental humidity, it is very easy to produce air oxidation, resulting in the surface exposed in the air will rust. Even if it is stored in a dry and naturally ventilated place, it will still rust after a long time; If the antirust film is rubbed away or washed away by precipitation in the whole process of transportation, it is very easy to rust. In order to make better progress and increase its antirust treatment time and service life, the cold drawn square steel will add the process of brushing antirust agent before the original factory.

The oil slick we talked about before is just due to the actual effect of antirust agent attached to the surface of cold drawn square steel. The purpose is to better improve the period of antirust treatment, which can show an excellent period of validity of antirust treatment for the processing and storage of cold semi-finished products. Application of cold drawn square steel and promotion of overall quality strength

To promote the application of cold drawn square steel and the overall strength of quality, in the whole process of effectively promoting the application performance of products, it is necessary to improve the use value characteristics of products, gradually improve their specific application and other advantages, and promote the reflection of the actual application effect from the overall strength of each product in the whole process, In order to improve the development ability of product use value characteristics, gradually improve the reflection of the overall strength of its quality application, develop the actual effect of the advantages of its overall application level, and then speed up the promotion of its specific characteristics by improving its application ability.

Nitrogen can dissolve metallography. When the cold drawn square steel is heated at 200 ~ 250 ℃ after rapid cooling, nitrogen compounds will precipitate, which will increase the hardness and compressive strength of the flange plate steel, and greatly reduce the plastic deformation and ductility, even if the steel shows blue ductility (aging ductility). If all carbon can be incorporated into martensite in the calcining temperature range, the plastic deformation of the steel will not be affected much. Only when the carbon content of the steel is high, because more pearlite and even ledeburite precipitate from the ionic crystal, the plastic deformation of the flange plate steel is greatly reduced. Introduction of anti rust measures for cold drawn square steel

After the square steel material is put into storage, it should be cleaned up frequently.

After cleaning the surface of general square steel, there is no need to apply oil, but for high-quality square steel, alloy thin square steel plate, thin-walled pipe, alloy square steel pipe, etc., the internal and external surfaces of the steel after rust removal need to be coated with anti rust oil before storage.

Square steel materials should be prevented from rain or impurities before storage. Materials that have been rain or contaminated should be cleaned by different methods according to their properties. For example, steel wire brush can be used for high hardness materials, cloth and cotton can be used for low hardness materials.

The square steel with serious corrosion should not be kept for a long time after rust removal, but should be used as soon as possible.

The rust layer of cold drawn square steel should be removed; It is not necessary to apply oil on the surface of general square steel after cleaning, but for high-quality square steel, alloy thin-walled steel plate, thin-walled pipe, alloy square steel pipe, etc., the internal and external surfaces should be coated with anti rust oil after rust removal before storage; Square steel materials should be protected from rain or impurities before storage. Materials that have been soaked or contaminated should be cleaned by different methods according to their properties, such as steel wire brush for high hardness, cloth, cotton for low hardness, etc; The square steel with serious corrosion should not be kept for a long time after rust removal, but should be used as soon as possible.

When the steel bar is cold drawn with the cold drawing rate, the value shall be determined by the test. Requirements for test determination: there shall be no less than 4 test pieces of the same batch in the same furnace. The corresponding cold drawing rate of each test piece shall be determined according to the cold drawing stress specified in the specification, and the average value of the test pieces shall be taken as the actual cold drawing rate of the batch of steel bars in the furnace. If the strength of steel bar is too high and the average cold drawing rate is lower than 1%, the cold drawing rate of 1% should still be adopted.

Cold drawing of different batches:

For the steel bars which are mixed and can not be distinguished from the furnace batch, the cold drawing rate can not be used during cold drawing. Moreover, the cold drawing rate and stress of several connected steel bars should be in accordance with the specification.

When we smelt the cold drawn square steel, the difficulty is the temperature, but when we smelt the cold drawn square steel, the important thing is also the temperature, so we need to know the temperature of flat steel in each period,

The starting forging temperature of cold drawn square steel should be understood as the allowable heating temperature of steel or alloy in heating furnace. Before the blank is taken out from the heating furnace and sent to the forging equipment for forging, according to the size of the blank, the distance between the heating furnace and the forging equipment, the temperature drop of the blank is several degrees to several degrees. Therefore, the forging temperature is lower, and the temperature drop of the blank should be minimized before forging.

The overburning temperature of steel is about 100-150 ℃ lower than the melting point, and the superheating temperature is about 50 ℃ lower than the overburning temperature, so the starting forging temperature of steel should be 150-200 ℃ lower than the melting point (or lower than the solidus temperature of state diagram). In addition, the carbon content has an important influence on the upper forging temperature of steel. The initial forging temperature decreases with the increase of carbon content, so the initial forging temperature usually decreases more with the increase of carbon content.

There is also the overheating of cold drawn square steel due to too high initial forging temperature or too long heating time, although it can be deformed by forging

It is difficult to completely eliminate the forging deformation for severe overheating. Therefore, the safe starting forging temperature should be determined to prevent overheating.

Requirements for determination of cold drawing rate of cold drawn square steel:

For the steel bars which are mixed and can not be distinguished from the furnace batch, the cold drawing rate can not be used during cold drawing. Moreover, the cold drawing rate and stress of several connected steel bars should be in accordance with the specification. During the loading and unloading of cold drawn square steel, we should try our best to avoid the direct contact between steel wire ropes or fasteners. For the shelf storing cold drawn square steel, we should pay attention to the separation of wooden or rubber plates from carbon steel members, In fact, we need to prepare hammer or wooden hammer, copper hammer and cold drawn flat steel wire brush and other special tools in advance.

When connecting the branch pipe on the main pipe, we should pay attention to the use of prefabricated cold drawn square steel. If we want to turn the pump oil pipe, the compression type square steel actually needs to be directly drilled on the main pipe to connect the branch pipe. At this time, we should pay attention to the use of drill and milling machinery for processing. If we want to use carbon arc gouging or plasma cutting, we actually need to use polishing machine to polish afterwards.

When cold drawn square steel is applied, we will notice that it is strictly forbidden to knock on its surface with a hammer. For cold drawn square steel can not be directly carried out with carbon steel support, it should be carried out directly between the support and the pipe with cold drawn flat steel sheet or plastic sheet.

In addition, in fact, it will be on the rubber plate or other insulating materials. In this case, it is to prevent the corrosion caused by carburization and potential difference. When the cold drawn square steel passes through the wall or floor, it should directly install a sleeve.

In fact, the gap between the sleeve of cold drawn square steel and the pipe should not be less than 10 mm. In addition, in the gap of cold drawn square steel, we should pay attention to adding a series of insulating materials. In addition, we should pay attention to that the insulating materials should not contain iron filings and rust, For its insulation, asbestos rope is usually used. Cold drawn square steel is a solid bar. Different from square pipe, hollow pipe belongs to pipe material. Unlike cold drawn square steel, steel is the material of various shapes, sizes and properties required by ingot, billet or steel pressure processing. Steel is an essential material for the construction and Realization of industrialization. It is widely used and has many varieties. According to the shape of cross section, steel can be divided into profiles, plates, pipes and metal products.

After that, we should pay attention to the cold drawn square steel itself, that is, forging the cold drawn square steel. In the actual production, the cold drawn square steel is forced to stretch the steel bar with the tensile stress exceeding the yield point strength of the original steel bar under normal temperature, so as to produce plastic deformation of the steel bar, so as to improve the yield point strength of the steel bar and save steel.

Cold drawing of square steel is carried out by means of cold technology, precise mould, drawing out all kinds of round steel, square steel, flat steel, angle steel and other special-shaped steel with high precision and smooth surface; Later on, the concept of cold drawing of steel bars is bound to save steel and improve the yield strength of steel bars. It is called cold drawing of steel bars that the tensile stress exceeds the yield strength but is less than the ultimate strength and causes plastic deformation.

Cold drawn square steel is mainly used in fine decoration, such as doors and windows. Then, about this product specification, i.e. in 3 & times; 3mm— 80× 80mm。

With regard to the use of cold drawn square steel, it should be noted that the steel products other than this equipment can be divided into sections, plates, pipes and metal products according to different cross-section shapes. In order to facilitate the production, ordering and supply of steel products and do a good job in business management, they can also be divided into heavy rail, light rail, large section steel, medium section steel, small section steel and many other varieties, The application of cold drawn square steel is based on the wide application of this steel.

The basic characteristics of cold drawn square steel are as follows

Cold drawn square steel is very diverse in appearance, specification and model. Since then, the way of commodity and specification and model are various. We can carry out relative cold drawn production according to different requirements, so that we can consider all kinds of production requirements. Cold drawn square steel also has the characteristics of precision angle of view. At the time of cold drawing skills processing, its production skills were very exquisite, the errors and omissions were very small, and the degree was very high.

Cold drawn square steel is also very smooth on the surface. For the steel products with cold drawing skills, its surface is smooth and its quality skills are very exquisite; Cold drawn square steel in the production of the time is also relatively less raw materials, in view of this cold drawing process is the raw material cold drawing forming deformation to achieve the required appearance, specification and size tolerance, the consumption of raw materials is very small. This relative to the traditional CNC lathe production and processing, nature is more saving natural materials, greatly saving the cost of production.

The basic production principle of cold drawn square steel is as follows:

For the production and processing of cold drawn square steel, as far as the stainless steel plate itself is concerned, cold drawing will be carried out at room temperature to cause plastic deformation and improve the tensile strength. The whole process is called cold drawing strengthening.

The basic principle of cold drawn square steel at the time of cold drawing strengthening is that the defect of lattice constant of stainless steel plate in plastic deformation increases, and the lattice constant of defect is seriously distorted, which will have a blocking effect on the deepening sliding of lattice constant, so the yield limit of stainless steel plate is improved, and the plastic deformation and ductility are reduced. The tensile strength of stainless steel plate decreases due to the thermal stress caused by plastic deformation. At the moment, the cold drawn building steel bars are stored at room temperature for 16-30 days or heated to 150-150 ℃ for a necessary time, which is called aging treatment.

After aging treatment, the yield limit of cold drawn square steel increases, the ultimate compressive strength also increases, and the plastic deformation decreases again. Only for cold drawn square steel, the tensile strength can be repaired due to the reduction of thermal stress in the whole aging process. Cold drawn square steel products in the shape, specification, model hierarchy, height characteristics:

According to the design of different shape of abrasive, cold drawn square steel products with different cross-section shape, different size tolerance. In addition to the cold drawn square steel, people should pay special attention to the angle of view of cold drawn steel, that is to say, the design scheme can be designed into oblique angle or arc immediately; The application of high-quality cemented carbide mold and its technical repair workers can ensure that the dimension tolerance of cold drawn square steel is accurate and accurate.

The surface of cold drawn square steel is bright and clean, and the raw materials are saved

After that, people should pay special attention to the cold drawing process. That is to say, the cold drawing process will make the raw material cold deformed to the required appearance, specification and size tolerance. Because of this, people should pay special attention to the fact that the loss of raw materials is very small, Relativity use of traditional CNC lathe machining drilling loss of raw materials, cold drawing of raw materials saved by the square steel is rich, very when the use of raw materials, raw material cost savings more obvious.

Cold drawn square steel production processing time and processing machinery saving:

Because of the precision and surface management, the cold drawn square steel products can be applied immediately. The more common ones include painting, sanding, bending and hole turning. In the future, the electroplating process can be carried out immediately after fine drawing according to the actual regulations. At the same time, the, It can also avoid a lot of machining time and save the cost of processing machinery.

In today's commonly used cold drawn square steel specifications and models, that is to say, there will be 18 * 18mm - 60 * 60MM; The materials include 46, a, 30Cr, 50Cr, 30CrMo, 50 CrMo, 30mn2a, 43crmo, 30MnSi, 45crmo, Hg Q2, q23, B, 20cr2mova, 65si2mna, 56crsia, 18mN, 50Mn, etc.

Cold drawn square steel is the key target of improving the yield ultimate compressive strength of building steel bar and saving stainless steel plate at the same time. And for the cold drawn square steel, I think that is to say, the use of cold technology, according to the grinding tool, pull out a variety of high-precision, surface smooth channel steel. Characteristics, application and processing technology of cold drawn square steel

Cold drawn square steel is a product with smooth and bright appearance, which can be processed according to the specified process. It can keep saving steel, improve the yield strength of the product, and greatly reduce the material. The cold drawing process is to achieve the required shape, dimension and tolerance of raw materials by cold deformation. The loss of raw materials is very small. Compared with the material consumed by traditional lathe machining, the material saved by cold drawing square steel is considerable, especially when the material consumption is large, the material cost saving is more obvious.

Characteristics, application and processing technology of cold drawn square steel

At the same time, cold drawn square steel can greatly improve the processing speed, save man hour, and for the accuracy of processing machinery, can improve the surface quality of products. Generally speaking, cold drawn steel products can be directly applied, such as spraying, sanding, bending, drilling, or direct electroplating after fine drawing according to specific standards, which saves a lot of machining time and the cost of configuring processing machinery.

Cold drawn square steel can be used in different industries, such as woodworking machinery, ceramic machinery, paper machinery, glass machinery, food machinery, construction machinery, plastic machinery, textile machinery, Jack, hydraulic machine, etc; It can also be used as electrical parts, such as motor shaft, fan shaft, sewing machine shaft, etc.

In addition, for some furniture products, especially metal furniture, cold drawn square steel will also be used. Processing of cold drawn steel: for the first cold drawing effect, take the steel bar to exert tensile stress on it, and the steel bar will deform. With the increase of tensile stress, the internal tensile stress of the reinforcement gradually expands. When the tensile stress inside the reinforcement exceeds the yield point a of the reinforcement and reaches C, the cold drawing is stopped and the load is removed. Cold drawn square steel refers to the use of advanced cold technology at room temperature, the selection of accurate mold, and the tensile stress higher than the original yield point strength of steel bars, forced tensile steel bars, so that steel bars produce plastic deformation, in order to improve the yield point strength of steel bars and save steel. The cold drawn square steel product has the characteristics of high precision and smooth surface. Introduction to mechanical properties of high quality cold drawn square steel: tensile strength (& sigma; b/MPa):315-430; Elongation (& Delta; 5/%):≥ 33。 Combined with the current application situation, cold drawn square steel is widely used. The main application examples are as follows: the product can be used for anchor bolts, plowshare, chimney, roof panel, rivets, low carbon steel wire, thin plate, welded pipe, pull rod, hook, bracket, welding structure, etc. It can also be used for rolling sheet and wire rod. In addition, it can also be used for cold-rolled and hot-rolled steel sheet and galvanized, tinned and plastic composite steel sheet made from it. It is widely used for roof panel, decorative panel, general dust removal pipe, packaging container, iron barrel, instrument case, switch box, protective cover and train carriage, etc. In addition to the above applications, there are many high-quality cold drawn square steel products that can be used for wire rod, such as cold drawn low-carbon steel wire or galvanized low-carbon steel wire, used for binding, tension fixation, steel mesh, rivet, etc. The formula for calculating the theoretical weight of square steel is the side length multiplied by the side length Х 0.00785=kg/m。 Its square steel side length (mm), cross-sectional area (CM), theoretical weight (kg / M), side length (mm), cross-sectional area(

Cm, theoretical weight (kg / M). In standard parts, the cross-sectional area and weight of square steel with side length of 105 to 250 mm are not listed. If necessary, it can be calculated by referring to the multiple of the data listed in the table. Knowledge sharing of heat treatment process of high quality cold drawn square steel: in actual processing, heat treatment is an important link. The heat treatment specification and metallographic requirements of the product are that hot rolling process is adopted for heat treatment. The gold phase is ferrite + pearlite. Cold drawn square steel is iron carbon with carbon content between 0.021% - 11%. In order to ensure its toughness and plasticity, the carbon content is generally not more than 7%. In addition to iron and carbon, the main elements of steel are silicon, manganese, sulfur, phosphorus, etc. these metal elements have different effects on cold drawn square steel.

In addition, there is molybdenum in cold drawn square steel, which can be used as carbonization agent to prevent steel from embrittlement and maintain the strength of steel at high temperature. It appears in many steels. Air hardened steel makes cold drawn square steel can be used in more occasions with excellent performance.

Due to the high cutting power, more heat is generated, and the thermal conductivity of cold drawn square steel is lower than that of stainless steel, only 1 / of that of medium carbon steel, so the cutting zone temperature is very high. When the cutting speed is less than 50 m / min, the cutting temperature is 200 ℃~ 250 ℃ higher than that of 45 steel. Therefore, the tool wear is serious and the durability is reduced.

In the past, the connecting rod of shock absorber was plated with hard chromium, so the corrosion resistance could not meet the requirements. Recently, heef25 microcrack chromium plating process has been used, so that the coating thickness of cold drawn square steel can reach 20 & plusmn; 5μ, And 10L & plusmn; 3μ The specification has a positive effect on the corrosion resistance of the connecting rod of the shock absorber.

When it comes to the advantages of cold drawn square steel, first of all, we should pay attention to its cold drawing rate, which refers to the ratio (%) of the total elongation of steel or steel bar and plastic deformation and the original length of steel bar during cold drawing. Within a certain limit, the larger the cold drawing stress or cold drawing rate is, the higher the yield strength is, and the lower the plasticity is.

One of the advantages of cold drawn square steel is that it can save a lot of materials: the cold drawing process will deform the raw materials to the shape, specification and tolerance we need, and the consumption of raw materials is very small. Compared with the material consumed by traditional lathe machining, the material saved by cold drawn square steel in processing is very considerable, especially when the material consumption is large, the material cost saving is more significant.

The advantage of cold drawn square steel is its high precision angle, the use of high-quality cemented carbide mold and the maintenance personnel. Make sure the tolerance is accurate. The surface of cold drawn square steel will be smooth. In detail, the advanced cold process will make the surface of cold drawn square steel smooth and bright.

Cold drawn square steel in shape and specification is also diversity: design different shapes of mold, cold drawn different cross-section shape, for different specifications of tolerance of cold drawn steel, in addition to what we call cold drawn square steel, in terms of its angle, that is, it can be directly designed as a right angle or fillet.

Cold drawn square steel also has the time and machinery saving in processing. Because the precision is accurate and the surface condition is good, the cold drawn square steel products can be used directly. The common ones include spraying, sanding, bending and hole turning. After that, the electroplating can be carried out directly after fine drawing according to the actual requirements, which saves a lot of machining time and the cost of configuring processing machinery. The specification of cold drawn square steel is expressed by side length. The steel with diameter of 85-160mm and square steel with side length of 85-154mm belong to large section steel; The steel with diameter of 38-80mm and square steel with side length of 50-75mm belong to medium section steel; Square steel with diameter of 36-10 mm and side length of 25-10 mm belongs to small section steel. The delivery length of cold drawn square steel can be divided into fixed length or double length. The selection range of length varies with the diameter and steel grade.

Relevant standards for appearance quality stipulate the appearance quality of cold drawn square steel, generally including that there shall be no harmful defects in use, the bending degree of cold drawn square steel delivered by straight bars must comply with the standards, the cold drawn square steel shall not have significant torsion, the tangent angle at both ends, the diameter (or side length), the bending angle of the cold drawn square steel, and the bending angle of the cold drawn square steel The value of ovality (or the difference of side length and diagonal) and its tolerance must comply with the standard.

It is a manufacturer of hot rolled square steel, hot rolled flat steel, cold drawn square steel, cold drawn flat steel, flat steel, round steel, angle steel, Tieyi steel and profiled steel.

Strong technical force, advanced rolling production line, excellent product quality, well received by the majority of users. Under the guidance of industry technology, relying on complete modern cold drawing equipment, scientific production technology, standardized product testing means and qualified staff, the product quality is ensured. The annual production capacity can reach more than 10000 tons. Welcome new and old customers to come to negotiate, for all aspects of cold drawn square steel, I believe many people are still very vague, after reading the following content, I believe we will let you know more about cold drawn square steel

Stress of cold drawn square steel:

For the steel bars of grade II, III and IV and No. 1 steel, after cold drawing, the cold drawing stress shall be used for the prestressed steel bars. However, after cold drawing, the cold drawing rate of steel bar exceeds the specified value, and the mechanical energy test should be carried out again.

Requirements for determination of cold drawing rate:

Cold drawing of different batches:

Cold drawing speed:

In order to make the steel bar fully deformed, it is necessary to have an appropriate cold drawing speed, generally 0.5 ~ 0. At the same time, it is required that after the cold drawing reaches the specified stress and cold drawing rate, immediately stop drawing for 2 ~ 3, then loosen the steel bar and end the cold drawing, so as to give the steel bar enough deformation time.

Cold drawing:

When cold drawing, only cold drawing rate or cold drawing stress is called single control. When cold drawing, cold drawing rate and cold drawing stress are applied at the same time, it is called double control. Using single control, the construction is simple and convenient. However, it is impossible to test the steel bars one by one, and the quality of cold drawing can not be guaranteed. Double control

These problems can be avoided. During cold drawing, if the stress has been reached and the cold drawing rate does not exceed the allowable value, it can be considered as qualified. However, if the cold drawing rate has been reached and the cold drawing stress has not yet reached the stress, the strength of the steel bar should be reduced. For prestressed reinforcement, double control must be adopted. Cold drawing of square steel; Cold drawing & quot; Rolling is a common treatment. It can not only produce square steel and other profiles, but also produce sheet metal pipes. Usually, when cold working is used, reciprocating hammer or other devices that can exert greater pressure are used to temper the raw materials in the forging process, so as to generate the required size and shape, generally including forging and die forging.

Compared with ordinary steel, cold drawn square steel has obvious performance improvement in all aspects, but it can not avoid some defects in long-term use. More is the common problem of steel & mdash& mdash; rust. Because the appearance of cold drawn square steel is composed of steel, it will inevitably rust to a certain extent when exposed to the air for a long time. Although the cold drawn square steel has good impact resistance, it can not completely avoid the generation of rust.

In order to solve this problem, optimize the characteristics of cold drawn square steel and effectively increase its working life, we must take corresponding measures& mdash; Phosphating. That is to say, aluminum or zinc is coated on the rusty spot of cold drawn square steel. At the same time of phosphating, a coating is rapidly formed on the rusty spot, that is, a phosphating protective layer is formed.

In addition, the phosphating process of cold drawn square steel is also an electrochemical process, so it can also enhance the metal density of the steel, reduce the harm of air and water erosion to the steel, and also help to optimize its comprehensive performance.

In the process of cold drawing square steel, phosphating can reduce and increase the effect, and increase the adhesion of finished products, which is beneficial to the practicability.

Another link of cold drawing square steel is finishing. With the steel after the finishing process, it can prevent its own debris adhesion and reduce the degree of corrosion.

In the production process of cold drawn square steel, it is necessary to strictly control and standardize the operation to avoid unnecessary dangerous events. Usually before cold drawing, the baffle must be protected in advance. If the baffle can not be set, the closed guide roller can be used, and the distance between cold drawing and winch can be adjusted to 90 DEG; The vertical state. Moreover, after the operation, the operator must not be too close to the cold drawing equipment, and must stand behind the baffle to avoid the crumbs during the cold drawing operation.

In addition to the above-mentioned precautions, we also need to carry out a thorough and detailed inspection of all equipment on a regular basis, so as to eliminate the safety defects caused by accidents. In addition, it is necessary to conduct a thorough inspection of the equipment, so as to avoid the occurrence of accidents.

If there is a need to apply fluorocarbon paint on the outer layer of cold drawn square steel, it should be noted that the coating thickness is about 20 mu; m-30μ In order to achieve the coating thickness of 50 & mu in the range of 50 m; M. It is necessary to determine the coating number according to the depth of the current paint layer color. If the color type of the paint layer is light, it is necessary to apply twice to completely cover the color of the bottom paint.

The environment temperature for engineering and drying of fluorocarbon corrosion-resistant paint should be above 5 ℃, the wind power level should not exceed 3, and the relative humidity should only be & le; 85%, and it can only be put into use after 7 days. The outer layer of cold drawn square steel must be flat, hygienic, colorless, without conspicuous color difference, dirt and oil spots; If there are stains, dirty dust and oil stains on the outer layer, they can be removed with wire brush and special cleaning solution or polished with coarse sand paper. After polishing, they can be used in engineering. Select special matching smooth putty for longitudinal scraping, mainly to make the bottom layer fine, smooth, no scratch, no small holes; Use 500 mesh water-resistant sand and special sand tools to finish careful grinding and polishing. There should be no obvious sand mark, sand hole and no hand pricking. The pressure of the air compressor should be 45kg / cm2 or more, and the interval between the paint outlet and the wall is 625px. For the brush dipped into the paint, the depth of the brush head hair dipped into the paint is also regular. If it is deeper than 1G of the brush head hair, it will also adhere to the paint. In this way, the painting will be distorted and the working cycle will be greatly shortened. For the brush with good paint, brush the steel slightly before painting; Scratch & quot; In this way, after the surplus paint is scraped off, it will be smoother when brushing, and it is also avoided to brush the surplus paint, or drop it to the clean position to be brushed or the ground. When coating the vertical outer layer of cold drawn square steel, brush from top to bottom; In the coating horizontal direction of the outer layer, it should be in accordance with the direction of sunlight. Brushing the overall process, must control the brushing force, film thickness.

Cold drawn square steel refers to the cold drawn process. Just now, due to the complex processing process, we often encounter some problems. Today, let's talk about the common deformation problems. In order to deal with this problem, first of all to control the long workpiece, this is more important, press on the milling machine platform or use two flat tongs. It is necessary to use the processing technology suitable for long workpiece, such as twice or twice rough and finish machining, select the appropriate tool, and try to be sharper, so as to avoid stress and deformation of workpiece; During rough machining, the workpiece should produce less heat as far as possible; It can also be considered to finish grinding after milling. Therefore, if we want to deal with the deformation of cold drawn square steel, we should first control its deformation, vibration of long workpiece and select appropriate processing technology. At the same time, we also need to pay attention to another problem, that is, the appearance and quality of cold drawn square steel at low temperature need to be improved. As far as the appearance of cold drawn square steel is concerned, there should be no cracks and necking in their local areas. In this case, the installation of cold drawing square steel is a basic guarantee in practice. When the temperature is lower than - 20 ℃, our practice will directly prohibit our cold drawing square steel series of cold bending operation. If cold drawn square steel is welded at negative temperature in winter, it is necessary to be careful to weld them as much as possible

It's indoors.

If possible, try to weld indoors, so as to ensure the quality of products to a greater extent. If welding is necessary to be carried out outdoors, we should also pay attention to that the ambient temperature should not be lower than - 20 ℃, and welding should not be carried out in snowy weather. When the cold drawn square steel is welded outdoors, we should also pay attention to that when the wind force exceeds grade 3, the wind proof method should be set directly. It is necessary for us to prohibit the welding of uncooled joints. When transporting and processing them, it is necessary to pay attention to prevent bumps or scratches. It is a kind of cold drawn steel, with smooth appearance and excellent hardness. It is widely used. Today, I will take you to understand its processing principle and product advantages. Cold drawn square steel is a kind of forged square cold drawn steel, which is used to forcibly stretch the steel bar at room temperature. The tensile stress exceeds the original yield point strength of the steel bar, causing plastic deformation of the steel bar, so as to improve the yield point strength of the steel bar and save steel. Cold drawn steel is a kind of round steel, square steel, flat steel, angle steel and other precision mold processing from high precision, smooth surface of special-shaped steel. Cold drawn steel at room temperature induces plastic deformation to improve yield strength. This process is called cold drawn strengthening.

The lattice defects of steel increase in the process of plastic deformation. Serious distortion of defects will hinder the progress of lattice sliding, so the yield point of steel increases and the plasticity and toughness decrease. Due to the internal stress caused by plastic deformation, the modulus of steel decreases. Cold drawn steel bars stored at room temperature for 15 ~ 20 days or heated to 100 ~ 200 ℃ for a fixed time is called aging treatment. After cold drawing, the yield point, ultimate tensile strength and plasticity of aged steel bars are improved. Due to the decrease of internal stress, the modulus can be recovered. This principle is often used in the construction site or prefabricated component factory to cold draw or cold draw the steel bar or low carbon steel wire according to the set, so as to improve the yield strength and save steel.

According to the needs of different scenes, we can design different molds to create more suitable products. We can draw cold drawn square steel with different cross-section shapes, different specifications and tolerances. The angle can be designed as right angle or fillet. We use high-quality cemented carbide molds and mold maintenance personnel to ensure accurate and uniform tolerances, The cold drawing process makes the surface of cold drawn square steel smooth and bright. The cold drawing process is to deform the raw materials to meet the required shape, specification and tolerance, with little consumption of raw materials.

I believe you've all seen it. Today we'll introduce how it is processed and what advantages it has. Cold drawn square steel refers to the forged square cold drawn steel, which is used to forcibly stretch the steel bar at room temperature. The tensile stress exceeds the original yield point strength of the steel bar, causing plastic deformation of the steel bar, so as to improve the yield point strength of the steel bar and achieve the benefit of saving steel. Cold drawn steel is a kind of round steel, square steel, flat steel, angle steel and other precision mold processing from high precision, smooth surface of special-shaped steel. The cold drawn steel at room temperature can induce plastic deformation to improve the yield strength. This process is called cold drawing strengthening. Cold drawing strengthening principle: the lattice defects of steel increase in the process of plastic deformation, the serious distortion of lattice defects will hinder the progress of lattice sliding, so the yield point of steel increases. After the special processing, the yield point, strength and plasticity of the product are improved. Due to the decrease of internal stress in the aging process, the modulus can be basically restored. This principle is often used in the construction site or prefabrication plant to cold draw or cold draw the steel bar or low-carbon steel bar according to the fixed, so as to improve the yield strength and save steel. Advantages of cold drawn square steel: different shapes of dies can be designed to make cold drawn square steel with different section shapes, specifications and tolerances into right angles or rounded corners. Use high quality cemented carbide mold and mold maintenance personnel to ensure the correct tolerance. The cold drawing process is to deform the raw materials to meet the required shape, specification and tolerance, with little consumption of raw materials.

Because of its accuracy and smooth appearance, it can also be used directly. Of course, it can also be directly electroplated after drawing according to the actual demand, which saves a lot of processing time and the cost of configuring processing machinery. Cold high-end technology and beautiful mold template, cold drawn square steel can become a variety of metal products made of steel, these metal products also have their own advantages, high precision, smooth surface, various forms. Cold drawn square steel products are widely used in daily life, mainly for mechanical equipment, electrical parts, furniture, metal, gold parts and so on. It refers to the steel produced by cold treatment, which is different from the products produced by traditional methods. Its appearance is smoother and more beautiful. During processing, the tensile stress exceeds the original yield point strength of the steel bar, causing plastic deformation of the steel bar, so as to improve the yield point strength of the steel bar and save steel. Cold drawn steel is round steel, square steel, flat steel The principle of cold drawing is to produce plastic deformation at room temperature, so as to improve the yield strength. This process is called cold drawing strengthening. The principle of cold drawing strengthening: the lattice defects of steel increase in the process of plastic deformation. Serious distortion of defects will hinder the progress of lattice sliding, so the yield point of steel increases and the plasticity and toughness decrease. Due to the deformation in the tensile process, the internal stress changes, which will reduce the strength of the steel. Storage at room temperature for 15 ~ 20 days or heating to 100 ~ 200 ℃ for a fixed time is called aging treatment. The yield point, ultimate tensile strength and plasticity of the aged steel bar after cold drawing are improved. Due to the decrease of internal stress in the aging process, the modulus can be basically restored, This principle is often used in the construction site or prefabricated component factory to cold draw or cold draw the steel bar or low carbon steel wire according to the set, so as to improve the yield strength and save steel.

Its advantage is that the shapes and specifications are diverse. According to different requirements and standards, products with different shapes can be made. Cold drawn square steel with different cross-section shapes, specifications and tolerances can be drawn. The angle can be designed as right angle or fillet. High quality cemented carbide dies and die maintenance personnel can be used to ensure the tolerance. The cold drawing process is to deform the raw materials, To achieve the required shape, specifications and tolerances, raw materials

Compared with the material consumed by traditional lathe, the material saved by cold drawn square steel is very considerable, especially when the material consumption is large, the material cost saving is more significant.

I don't know how much you know about the quality inspection of cold drawn square steel. It is widely used in our daily life, especially in the construction industry. Today, I'd like to introduce the following quality inspection of cold drawn square steel to you. It should be helpful to you, for grade II, III, IV reinforcement and grade IV reinforcement, After cold drawing, it should be used as prestressed reinforcement and subject to cold drawing stress, but after cold drawing, if the larger cold drawing rate exceeds the specified value, the mechanical energy test should be carried out again to determine the requirements of cold drawing rate: when the cold drawing rate is used, the value should be determined by test. According to the test requirements, more than one product of the same batch should be taken randomly, and the average value should be taken as the actual cold drawing rate of the batch of steel bars in the furnace. If the strength of reinforcement is high, the average cold drawing rate is less than 1%, and the cold drawing rate of reinforcement should still be 1%. Cold drawing of different batches: for mixed and indistinguishable reinforcement, the cold drawing rate can not be used to describe the cold drawing process, the connected reinforcement shall be cold drawn, and the cold drawing rate and stress of each reinforcement shall comply with the specification. Cold drawing speed: in order to make the reinforcement fully deformed, it needs appropriate cold drawing speed, generally 0.5 ~ 0. At the same time, it is required to relax the steel bar after the specified stress and cold drawing rate, and give the steel bar enough deformation time after the cold drawing.

In the process of processing, only the rate or stress becomes single control. In the process, the rate and stress should be applied at the same time, which is called double control. The single control construction is simple, but the steel bars with uneven material can not be detected one by one, and the cold drawing quality can not be guaranteed. The double control method can avoid the above problems. If the stress has been reached in the cold drawing process, and the cold drawing rate does not exceed the allowable value, it can be considered as qualified, but if the cold drawing ratio has been reached, the cold drawing stress can not reach the stress, The reinforcement with lower strength shall be used. The heat treatment of cold drawn square steel is heating and cooling to change the physical properties of metal. Heat treatment can improve the microstructure of cold drawn square steel. The toughness, hardness and wear resistance of cold drawn square steel are obtained by heat treatment. Heat treatment includes quenching, tempering, annealing and surface hardening.

Hardening: heating the metal evenly to an appropriate temperature, then rapidly immersing it in water or oil for quenching, or cooling it in air or freezing zone, so as to obtain the required hardness.

Tempering: the cold drawn square steel will become brittle after hardening. At the same time, the stress caused by quenching and quenching can cause the cold drawn square steel to be broken by light hitting. To eliminate brittleness, tempering can be used. Tempering is to reheat the steel to an appropriate temperature or color, and then quench it. Although tempering slightly reduces the hardness of cold drawn square steel, it can increase the toughness of cold drawn square steel and reduce its brittleness.

Annealing: annealing is to eliminate the internal stress of cold drawn square steel parts and Lehua steel parts. Annealing method is to heat the steel to a temperature higher than the critical temperature, and then put dry ash, lime, asbestos or sealed in the furnace to cool it slowly. We know that all metals are corroded and rusted, and cold drawn Fanggang is no exception. Cold drawn square steel is likely to be corroded in use, so how should we deal with the corroded square steel? What should be used to prevent corrosion?

After the cold drawn square steel materials are put into storage, they should be cleaned up frequently. If there is rust, the rust layer should be removed.

Generally, after the surface of cold drawn square steel is cleaned, there is no need to apply oil, but for high-quality square steel, alloy thin square steel plate, thin-walled pipe, alloy square steel pipe, etc., after rust removal, the internal and external surfaces should be coated with anti rust oil before storage.

Square steel materials should be prevented from rain or impurities before storage. Materials that have been rain or contaminated should be cleaned by different methods according to their properties. For example, steel wire brush can be used for high hardness materials, cloth and cotton can be used for low hardness materials.

The square steel with serious corrosion should not be kept for a long time after rust removal, but should be used as soon as possible. Cold drawn square steel is cold technology, accurate mold, pull out all kinds of high precision, smooth surface angle steel. Products are widely used in machinery, light industry, gold, standard parts, bicycles, automobiles, motorcycles, textile machinery, transformers and other machinery industries.

The shape and specification of cold drawn square steel are various. Design different shapes of mold, cold drawing out different cross-section shape, different size tolerance. Angle can be made into right angle or fillet, high precision, using high-quality cemented carbide mold and technical personnel, accurate tolerance, smooth surface.

The cold drawing process makes the surface of cold drawn steel products smooth and bright, and saves a lot of materials; Cold drawn steel is the raw material cold deformation to the required shape, the required specifications and tolerances, the loss of raw materials is very small, compared with the traditional lathe machining loss of materials, cold drawn square steel material saving is very considerable, especially when the material consumption is large, the material cost saving is more significant.

Cold drawn square steel in the selection of appropriate materials, so as to produce a perfect cold drawn square steel, after the selection of materials can be processed, in the processing should pay close attention to each step of cold drawn square steel, to cold drawn square steel can be used.

In the purchase of cold drawn square steel products, in addition to pay attention to the factory inspection or quality certificate of the products, we should pay attention to the quality of the business, and not greedy for cheap, we can take some actions on our own initiative. At present, the cold drawn square steel measuring liquid in small bottles on the market is small in volume, light in weight, easy to carry, low in cost and simple in test operation.

The quality of cold drawn square steel is not only determined by its chemical composition, but also by its properties, purity and other factors. For the determination of these factors, it is obvious that the determination liquid of cold drawn square steel is effective, and only with the help of relevant tests. The common treatment of cold drawn square steel mainly includes rolling, drawing and forging. On the cold drawing of square steel rolling, is the steel into the gap between the rotating roll, because the pressure roll part of the material is reduced, the length of the increase in pressure processing.

It is commonly used in the production of steel production, mainly producing profiles, plates, pipes; It can be divided into cold rolling and hot rolling. The drawing of cold drawn square steel refers to the rolling drawing of metal blank and die hole

When the section is reduced and the length is increased, it will also be used for cold working.

The forging of cold drawn square steel is a kind of pressure processing using reciprocating hammer impact force or pressure change to make the material into the required shape and size. Generally divided into forging and die forging, used for the production of large profiles, open billet section size larger materials.

According to the corresponding production process, the cold drawn square steel products show the characteristics of diversity in shape gauge. The cold drawn steel with different cross-section shape and different specification tolerance can be produced by designing different shapes of dies. The angle should also be designed as right angle or fillet; Cold drawn square steel has the characteristics of high accuracy, the use of high-quality cemented carbide mold and mold repair personnel to ensure accurate tolerance.

The surface of cold drawn square steel products is smooth, and the cold drawing process makes the surface of cold drawn steel products smooth and bright; Cold drawn square steel products can also save a lot of materials. This cold drawing process will make the raw materials cold deformed to the required shape, specification and tolerance, and the consumption of raw materials is very small. Compared with the materials consumed by traditional lathe machining, the material saved by cold drawn steel is very considerable, especially when the material consumption is large, the material cost saving is more significant. Cold drawn square steel is the application of cold technology, through the accurate mold, pull out all kinds of high precision, appearance angle steel. Products are widely used in machinery, light industry, metal, standard parts, bicycles, automobiles, motorcycles, textile machinery, transformers and other machinery industries.

The cold drawn square steel technology makes the appearance of the products bright and the materials economical; Cold drawn square steel is to cold deform the original data to the required shape, required specifications and tolerances. The consumption of raw materials is very small. Compared with the data consumed by traditional lathe machining, the data saved by cold drawn square steel is considerable, especially when the amount of data is large, the saving of data cost is more significant.

Cold drawn square steel in the selection of appropriate information, so that the ability of cold drawn square steel, after the selection of information can stop processing, in the processing should pay attention to each step of cold drawn square steel, to cold drawn square steel can be used.

In the whole process of cold drawing of cold drawn square steel, for the sake of product quality, it is necessary to have a good understanding of cold drawing operation. First of all, for the cold drawing stress, the cold drawing stress should be used for the steel bars of grade II, III, IV and No. 5 steel which are used as prestressed steel after cold drawing.

However, after cold drawing, the large cold drawing rate exceeds the standard value, and the mechanical energy experiment should be stopped. The second is to meet the requirements of cold drawing rate measurement, that is to say, when the cold drawing rate is used to cold draw square steel, the value should be confirmed by the experiment.

Cold drawn square steel can be used in different fields, such as various mechanical equipment: woodworking machinery, ceramic machinery, paper machinery, glass machinery, food machinery, construction machinery, plastic machinery, textile machinery, Jack, hydraulic machine, etc; It can also be used for electrical parts, such as motor shaft, fan shaft, sewing machine shaft, etc. Cold drawn square steel can be made into various cross-section forms to meet the needs of service conditions; Cold drawn square steel can make steel produce great plastic deformation, so as to improve the yield point of steel, so as to avoid delamination and interlayer; The residual stress has a certain influence on the performance of steel members.

The specification of cold drawn square steel is expressed by side length. The steel with diameter of 85-160mm and side length of 85-154mm belong to large section steel; Steel with diameter of 38-80mm and square steel with side length of 50-75mm belong to medium section steel; Square steel with diameter of 36-10 mm and side length of 25-10 mm belongs to small section steel. The delivery length of cold drawn square steel can be divided into fixed length or multiple length. The selection range of length varies with the diameter and steel grade.

The appearance quality of cold drawn square steel is stipulated, which generally includes no harmful defects in use, the bending of cold drawn square steel delivered by straight bar must meet the standard, the cold drawn square steel must not have significant torsion, and the provisions and tolerance values of tangent angle, diameter and ovality at both ends must meet the standard.

For the corresponding heat treatment method of cold drawn square steel, the first thing to pay attention to is normalizing, which will heat the steel or steel parts in the cold drawn square steel to the critical point AC3 or ACM, maintain the appropriate temperature above ACM for a certain time, and then cool in the air to obtain the pearlite heat treatment process.

The tempering treatment in the corresponding heat treatment mode of cold drawn square steel will also heat the quenched workpiece to the appropriate temperature below the critical point AC1 for a certain time, and after that, it should be noted that it must be cooled with the one that meets the requirements. In this regard, to a large extent, it is also a heat treatment process that can obtain the required heat and properties. The tempering and high temperature processing of cold drawn square steel is to heat the steel from the newly added furnace to the temperature of 850 ℃, and then use annealing. Although the hardness of the product will increase during quenching, the bending capacity of the raw material will increase and the brittleness will continue to decrease.

If the cold drawn square steel is repeatedly tempered, the cold drawn square steel will become brittle. If the cold drawn square steel is overheated or annealed, it is easy to react, which will lead to tapping and damage of the product.

According to the high operating environment of cold drawn square steel, the raw materials with appropriate physical changes should be selected, so as to provide convenience for the rational use of cooperative iron and steel enterprises. However, in a word, cold drawn metal materials are less malleable than most cold drawn raw materials, because it is easy to cause fracture problems. The angle of cold drawn bar can be arranged at right angles or 50 degrees. In this way, the cold drawn metal material will be directly formed in the process of plastic processing.

Cold drawn square steel is irregular after machining, the emergence of this problem is basically related to the following aspects: cold drawn special-shaped steel is not detected in advance; It's time to go overboard; The production process is not very good; They didn't process the stress value.

The actual cold drawn square steel belongs to the kind of semi-finished cold drawn steel. After cold drawing and sanding, the cold-rolled flat iron is sandblasted and sprayed separately. The raw materials for processing cold-rolled special-shaped steel are imported rectangular billets, and the hot-rolled square steel is hot-rolled forming, annealing, surface treatment and other processes. If the cold drawn steel is compared with the common profiles, the detailed parameters of the advantages and disadvantages can be obtained

. According to the process difference, cold drawn square steel and cold rolled square steel will be produced. Different steel will encounter different problems in the processing. Because the cold drawn square steel is a kind of wear-resistant steel, the cold drawn square steel after water toughening treatment can obtain higher plasticity and impact toughness.

Cold drawn square steel is sometimes processed by cutting. Due to the high cutting power, more heat is generated, and the thermal conductivity of cold drawn square steel is lower than that of stainless steel, only 1 / of that of medium carbon steel, so the cutting zone temperature is very high. When the cutting speed VC & amp; amp; lt; When the cutting temperature is 50 m / min, the cutting temperature is 200 ℃ ~ 250 ℃ higher than that of 45 steel. Therefore, the tool is seriously worn and the durability is reduced.

In the cutting process, due to the large plastic deformation, austenite transforms into fine-grained martensite, resulting in serious hardening of cold drawn square steel. Before machining, the hardness is generally hb200-220, after machining, the surface hardness can reach hb450-550, and the depth of hardened layer is 0.1-0.3mm, which is several times higher than that of 45 steel. Severe work hardening increases the cutting force, aggravates the wear of the tool, and also easily causes the tool to crack and damage.

The linear coefficient is similar to that of brass. At high cutting temperature, local thermal deformation occurs, and the dimensional accuracy is not easy. When cutting cold drawn square steel, rough machining should be carried out. After the workpiece is cooled, finish machining should be carried out to improve the dimensional accuracy of the workpiece. The toughness is 8 times that of 45 steel, and the chip is not easy to bend and break during cutting.

Although there are many shortcomings in the cutting process of cold drawn square steel, cold drawn square steel can change the mechanical and physical properties of metal materials by heat treatment, so as to improve its cutting performance. Customized cold drawn square steel can save processing time and cost, because it is more accurate in precision and convenient in surface condition, so it can be used directly. When it is spraying, sanding, bending or drilling, it will be directly electroplated after fine drawing according to the actual requirements, which saves a lot of machining time and the cost of configuration processing machinery.

When customizing cold drawn square steel, the raw materials will be directly cold deformed to the shape, specification and tolerance we need. The loss of raw materials is relatively small. Compared with the loss of materials in traditional lathe processing, the material saved is also very objective; And when the material consumption is relatively large, the material cost saving is more significant.

Custom cold drawn square steel has high precision, using high-quality cemented carbide mold and having mold repair personnel, accuracy and accuracy in tolerance. It makes the surface of custom cold drawn square steel smoother. It can be used in gold tools and auto parts, as well as standard parts, fasteners and machinery.

Customized cold drawn square steel can be cooled under normal temperature conditions, and accurate molds have been developed. In view of this, different kinds of high precision can be pulled out. The surface of cold drawn square steel is relatively smooth, and the cross-section shape is also square. According to the process difference, cold drawn square steel and cold rolled square steel will be produced. Different steel will encounter different problems in the process. Because the cold drawn square steel is wear-resistant steel, the cold drawn square steel after water toughening treatment can obtain higher plasticity and impact toughness.

The linear coefficient of cold drawn square steel is similar to that of brass. When the cutting temperature is high, local thermal deformation will occur, and the dimensional accuracy is not easy. When cutting cold drawn square steel, rough machining should be carried out, and the workpiece should be finished after cooling to ensure the dimensional accuracy of the workpiece. The toughness is 8 times higher than that of 45 steel, and the chip is not easy to bend and fracture.

Although there are many shortcomings in the processing of cold drawn square steel, it can change the mechanical and physical properties of metal materials by heat treatment, so as to improve its cutting performance. If it is necessary to apply fluorocarbon paint on the surface of cold drawn square steel, the thickness of the paint film is about 20-30um. In order to achieve the thickness of the paint film is about 50um, about 50um. According to the color of the selected topcoat to judge the number of topcoat coating, if the topcoat color is light color, it needs to spray twice to completely cover the color of the intermediate paint.

The temperature of the construction and drying site of fluorocarbon paint must be above 5 ℃, the wind force is lower than grade 3, and the relative humidity shall not be greater than 85%. It can only be delivered for use after 7 days. The surface of cold drawn square steel must be flat, clean, uniform in color, without obvious color difference, dust and oil stains; The surface dirt, dust and oil stain shall be removed with wire brush and synthetic detergent, or polished with coarse abrasive cloth, and the construction can be carried out after uniform polishing.

The special matching smooth putty is used for vertical scraping to make the base surface fine, smooth, flat, without scratch and pore; Use 500 mesh water-resistant sand, cooperate with special sand plate for fine grinding, no obvious sand mark, sand hole and no hand pricking by visual inspection. The air pressure of the air compressor should be above 45kg / cm2, and the distance between the mouth and the wall should be 25cm.

For the brush dipped in the paint, the immersion length of the bristles is particular. If it exceeds half of the bristles, the bristles will also be stained with the paint, so that the brush will deform and its life will be greatly shortened. A good paint brush should be wiped gently before brushing, so that after the extra paint is scraped off, the brushing will be smoother and the extra paint will be prevented from dripping to the clean area to be brushed or the ground.

Brush the vertical surface of cold drawn square steel from top to bottom; The horizontal surface should be painted in the direction of sunlight; The surface of wood shall be painted according to the grain of wood. The whole process of brushing is better than brushing strength, and the thickness of paint film is uniform. When cold drawing square steel is processed, it is usually carried out at room temperature. Cold drawing can produce plastic deformation and improve yield strength. This process is called cold drawing strengthening. The principle of cold drawn square steel in cold drawing strengthening is that the lattice defects of steel increase in plastic deformation, and the serious lattice distortion of defects will hinder the progress and slip of lattice, so the yield point of steel increases and the plasticity and toughness decrease. Because of the internal stress in plastic deformation, the modulus of steel decreases.

At this time, the cold drawn steel bar is stored at room temperature for 15-20 days or heated to 100-200 ℃ for a fixed time, which is called aging treatment. After aging treatment, the yield point of cold drawn square steel increases, the ultimate tensile strength also increases, and the plasticity continues to decrease. Because of the aging process

Because of the reduction of the internal stress, the modulus can be basically restored.

It is very important to grasp the stress of cold drawn square steel. After cold drawing, the cold drawn stress should be used for prestressed reinforcement. But after the steel cold drawing, the cold drawing rate exceeds the specified value, and the machine can execute again. It is also important to measure the cold drawing rate of cold drawn square steel.

In cold drawing, the operation control value is determined by the experiment. For cold drawn section steel, it is required that the number of test pieces in the same furnace and batch should not be less than, and the corresponding cold drawing rate should be determined for each test piece according to the cold drawing stress specified in the example, and the symmetrical value of the test piece should be taken as the actual cold drawing rate of the batch of steel bars in the furnace. If the strength of steel bar is on the high side and the average cold drawing rate is lower than percent, the cold drawing rate of steel bar should still be controlled according to percent. The cold drawing strengthening principle of cold drawn square steel is that the lattice defects of steel increase during plastic deformation, and the serious lattice distortion of defects will hinder the progress of lattice sliding. In this way, the yield point of steel will be improved, and the plasticity and toughness will be reduced. Because of the internal stress caused by plastic deformation, at this time, the modulus of steel will be reduced.

The cold drawing strengthening principle of cold drawn square steel means that the cold drawn steel bars are stored at room temperature for 15-20 days or heated to 100-200 ℃ for a certain period of time. In this process, to a large extent, it is called aging treatment. The yield point and ultimate tensile strength of the cold drawn steel bars after aging treatment will be improved, The plasticity will continue to decrease.

Because of the reduction of internal stress during aging, the modulus of cold drawn square steel will basically recover. This principle is often used in the construction site or prefabricated component factory. When the steel bar or low carbon steel wire rod is cold drawn or cold drawn, to a large extent, it can improve the yield strength to save steel.

The characteristics of cold drawn square steel products, because it is the primary information of light steel structure, in the selection of steel plate or steel strip cold bending formed. In addition to the cold-formed steel will be used in different types of building structures, that is, it will be widely used in vehicles, agricultural machinery and other related aspects.

Cold drawn square steel products have the characteristics of shape and specification diversity. As far as the form and specification of cold drawn square steel products are concerned, they are also diverse. As far as this point is concerned, we can actually carry out corresponding cold drawn production according to different needs. In this way, we can meet various needs of production. Cold drawn square steel products in the production skills are delicate, errors are small, in view of this, its degree is also very high. When it comes to cold drawn square steel, that is to say, under normal temperature conditions, the steel bar will be forced to stretch with the tensile stress exceeding the original yield point strength of the steel bar, and in this case, the steel bar will produce plastic deformation, so as to improve the yield point strength of the steel bar and save steel. Cold drawing square steel will be cold technology, and then it will be used to produce different kinds of high-precision and smooth surface round steel, square steel, flat steel, angle steel or other special-shaped steel.

The concept of cold drawing on cold drawn square steel can also save steel and improve the yield strength of steel bar. After that, the tensile stress that will exceed the yield strength and be less than the ultimate strength will stretch the steel bar to produce plastic deformation, which is called cold drawing.

If the cold drawn square steel equipment is skilled, it can process products of different shapes. In this way, the length of parts produced by the equipment to a large extent depends on the type and thickness of raw materials, and it directly determines the power of the machine and the size of its installation tools. Before starting up the equipment, it is necessary to check whether the parts are short of oil, and then check whether the safety protection is reliable after moving down.

When the cold drawn square steel equipment is in use, the pneumatic oil pump is to keep the pressure of the system within the specified range. If the pressure exceeds the specified range, the cold drawn square steel equipment will damage the components to a great extent. When it is applied in practice, it is inevitable to waste power.

When using the cold drawn square steel equipment, we should pay attention to adjust the position of the cold drawn square steel equipment and the angle it needs, the length of the equipment under the positioning, and the operation performance. In this way, we should also put the workpiece directly into the bending die box. After positioning, we can complete the processing by pressing the switch. When it comes to the advantages of cold drawn square steel, first of all, we should pay attention to its cold drawing rate, which refers to the ratio (%) of the total elongation of steel or steel bar and plastic deformation and the original length of steel bar during cold drawing. Within a certain limit, the larger the cold drawing stress or cold drawing rate is, the higher the yield strength is, and the lower the plasticity is.

One of the advantages of cold drawn square steel is that it can save a lot of materials: the cold drawing process will deform the raw materials to the shape, specification and tolerance we need, and the consumption of raw materials is very small. Compared with the material consumed by traditional lathe machining, the material saved by cold drawn square steel in processing is very considerable, especially when the material consumption is large, the material cost saving is more significant.

The advantage of cold drawn square steel is its high precision angle, the use of high-quality cemented carbide mold and the maintenance personnel. Make sure the tolerance is accurate. The surface of cold drawn square steel will be smooth. In detail, the cold drawing process will make the surface of cold drawn square steel smooth and bright.

Cold drawn square steel in shape and specification is also diversity: design different shapes of mold, cold drawn different cross-section shape, for different specifications of tolerance of cold drawn steel, in addition to what we call cold drawn square steel, in terms of its angle, that is, it can be directly designed as a right angle or fillet.

Cold drawn square steel is still in progress

Processing time, as well as its processing machinery savings. Because the precision is accurate and the surface condition is good, the cold drawn square steel products can be used directly. The common ones include spraying, sanding, bending and hole turning. After that, the electroplating can be carried out directly after fine drawing according to the actual requirements, which saves a lot of machining time and the cost of configuring processing machinery. The corresponding heat treatment method adopted by cold drawn square steel, first of all, it is necessary to pay attention to normalizing, which will heat the steel or steel parts in cold drawn square steel to the appropriate temperature above the critical point AC3 or ACM for a certain time, and then cool them in the air to obtain pearlite heat treatment process.

The heat treatment of cold drawn square steel also includes annealing, that is to say, the hypoeutectoid steel workpiece should be heated to 20 & mdash above AC3; The heat treatment process of cooling slowly with the furnace (or buried in sand or lime) to below 500 ℃ and cooling in air after holding for a period of time; For this solution heat treatment, the alloy should be heated to the high temperature single-phase region to keep constant temperature, so that the excess phase can be fully dissolved in the solid solution, followed by rapid cooling to obtain supersaturated solid solution.

The aging treatment in the corresponding heat treatment of cold drawn square steel means that after solution heat treatment or cold plastic deformation, the properties of the alloy will change with time when it is placed at or slightly higher than room temperature; When it comes to solid solution treatment, all phases in the alloy will be fully dissolved, solid solution will be strengthened, toughness and corrosion resistance will be improved, stress and softening will be eliminated, so as to continue processing and forming.

The aging treatment in the corresponding heat treatment mode of cold drawn square steel can improve the strength after the precipitation of strengthening phase is heated and kept warm, so that the precipitation of strengthening phase can be precipitated and hardened; Quenching is a heat treatment process in which the steel is austenitized and then cooled at an appropriate cooling rate to make martensite and other unstable structural transformation occur in the whole or a certain range of the cross section of the workpiece.

The tempering treatment in the corresponding heat treatment mode of cold drawn square steel will also heat the quenched workpiece to the appropriate temperature below the critical point AC1 for a certain period of time. After that, it should be noted that it must be cooled with the one that meets the requirements. In this regard, to a large extent, it is the heat treatment process that can obtain the required and performance. When it comes to the hardness index of cold drawn square steel, when it comes to the ability of hard objects of metal materials to collapse the surface, it is called hardness. According to the test and scope of application, hardness can be divided into Brinell hardness, Rockwell hardness, Vickers hardness, shore hardness, microhardness and high temperature hardness. For cold drawn square steel, there are Brinell hardness, Rockwell hardness and Vickers hardness.

For Brinell hardness (HB) of cold drawn square steel, steel ball or cemented carbide ball with fixed diameter shall be used to measure the indentation diameter (L) on the surface of the sample with the specified test force (f) pattern. After the specified holding time, the test force shall be removed. The Brinell hardness value is based on the test results

Cosmetic Bag

Cosmetic bags are cosmetic bags, such as mascara, lip gloss powder, eyebrow pencil, sunscreen cream, oil absorbing paper. According to the function, it is divided into multi-functional professional cosmetic bag, simple cosmetic bag for tourism and small household cosmetic bag. Cosmetic bags are divided into nylon cloth cosmetic bag, cotton cosmetic bag, PVC cosmetic bag and Pu cosmetic bag according to material.

The purpose of cosmetic bags is to make up for makeup when going out. I think it's OK to put lip gloss, powder and water spray. As for eye shadow brushes and so on, they should be put in the residence, so the bags will not be too heavy, and it will be enough.

Cosmetic bags are all kinds of bags used to hold cosmetics. Generally, they are used to pack cosmetics. In more detail, they are divided into multi-functional professional cosmetic bags, simple cosmetic bags for tourism and small household cosmetic bags.

Professional cosmetic bag with multiple functions, multiple layers and storage bags. It is mainly used by professional makeup artists.

Tourist cosmetic bag, usually easy to carry. Few cells, but complete functions. Common cosmetics and toiletries can be placed.

Household small cosmetic bags have a wide range of styles and types. The design, color and quality are also uneven. More small cosmetic bags are promotional products of cosmetic companies. Gifts when buying cosmetics.

Materials: 1 piece of kapok thread (yellow and water color), cloth (the one that does not come off the thread at the edge is better, here is the kitchen RAG), 1 button and sewing needle.

1. First weave two rows of blue thread with needle weaving method and hook 20 needle braids.

2. Then change the color, connect the yellow line with the blue line, and weave two lines. By analogy, change the thread every two rows, weaving 38 rows in total.

3. On line 39, start knitting from the second needle eye at both ends, and close one needle at both ends. The number of stitches in line 40 is the same as that in line 39.

4. Subtract 1 needle at both ends of line 41. Similarly, subtract 1 needle at both ends of lines 42-54. Line 54 reduced to 4 stitches.

5. Cut a piece of cloth with the same size as the fabric just now, overlap with the fabric, and lock the edge with wool worn on the needle.

6. Then fold it. When the bag is partially hemmed, it is sewn in a cross shape.

7. Sew a buttonhole on the cover and a button on the handbag.

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