Cold rolled steel DC01--DC07

Cold-rolled sheet refers to the steel produced by cutting the cold-rolled coil or plastic deformation of the hot-rolled steel sheet in the cold mill. Cold-rolled plates have more accurate dimensional tolerances, better surface quality and improved mechanical properties than hot-rolled plates. Cold rolling can produce thinner steel sheets (less than 0.8-1.0 mm), which can not be produced by hot rolling mills until now.

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The main industries that consume cold-rolled steel sheet include construction, machinery manufacturing, automotive, white goods and consumer goods.

In the field of construction, cold-rolled sheet is mainly used for the production of steel structures, curved closed and open profiles, facade members, doors, etc.

In the manufacture of transport machinery and white goods, cold-rolled sheets are mainly used in the manufacture of body and load carrying components for automobiles and vehicles. The cold-rolled sheet should have good formability and a surface suitable for various coating material applications.

The steel is also used to make cutlery, packaging materials and household goods for a variety of purposes. Big consumers of cold-rolled sheet include service metal centers, which serve different industries from construction to instrumentation engineering. These companies use high-precision automation equipment to cut, bend, machine and drill goods and parts made of cold-rolled steel sheets.

Classification, product range and properties of cold rolled steel plate

Cold rolled steel requirements applicable in different countries (e.g. EN 10130, EN 10268, EN 10209, ASTM A1008 / A1008M, DSTU 2834, GOST 16523, GOST 9045 and GOST 17066) The range of steel types and sizes, applications (copying, cold forming, enamel, general use, etc.), mechanical properties, surface quality, and other parameters are specified.

Cold-rolled sheet in line with European standards

The most commonly followed European production standards are EN 10130, EN 10268 and EN 10209.

EN 10130 is suitable for cold-formed uncoated low carbon DC01, DC03, DC04, DC05, DC06 and DC07 steel grades with a minimum width of 600 mm and a minimum thickness of 0.35 mm

EN 10268 relates to cold-rolled flat steel with a thickness of 3 mm or thinner and with a high yield strength suitable for cold forming. This reference is applicable to the following cold-rolled steel grades with different chemical compositions and mechanical properties:

B - Heat-treated steels (HC180B, HC220B, HC260B, HC300B), after heating to 170° C for 20 minutes, the reference yield strength has a certain increase

LA - Low alloy/microalloying steels (HC260LA, HC300LA, HC340LA, HC380LA, HC420LA, HC460LA, HC500LA) that contain one or more alloying elements, such as niobium, vanadium or titanium, in order to achieve the desired yield power

Y - inclusion-free steels (HC180Y, HC220Y, HC260Y) whose composition is controlled to improve plastic deformation r and strain hardening n

I - Isotropic steel (HC220I, HC260I, HC300I), minor parameter of plastic deformation r

The sheet is supplied as a finishing material only. Normally, rolled steel is treated with oil. In this case, both sides should be evenly coated with a neutral dry cleaning oil for rust prevention, so as to avoid corrosion within three months of normal packaging, transportation, loading and unloading and storage. The oil should be able to be removed with an alkaline solution or a common solvent. According to EN 10130, the surface quality of cold-rolled sheets is "A" or "B", except for LA steel, which can only have an "A" type surface quality. Cold-rolled sheets can also be used for metal coating by immersing the material in a metal bath, using electrolytic deposition methods, and/or applying organic and other types of coatings. If such coatings are required, they should be indicated in the request or order form.

EN 10209 for enamels of rolled steel grades DC01EK, DC04EK, DC06EK, DC03ED, DC04ED and DC06ED of 600 mm or more in width and 3 mm or less in thickness. The standard specifies the main requirements for the chemical composition, mechanical properties, surface quality and test methods of cold-rolled steel plates. The dimensions and shape tolerances of such cold rolled steel are specified in ЕN 10131.

Cold-rolled coils in accordance with Ukrainian and CIS standards

In Ukraine and the CIS countries, the main criteria include:

DSTU 2834 and the similar GOST 16523 standard are suitable for general application materials made of high quality and ordinary carbon steel with a production width of 500 mm or more and a thickness not exceeding 3.9 mm inclusive. According to its ultimate strength, steel grades are divided into the following strength groups: K260V, K270V, OK300V, K310V, K330V, K350V, OK360V, OK370V, K390V, OK400V, K490V. Based on surface finish, products are classified into Class I (Ultra finish), Class II (Ultra finish) and Class III (Ultra finish). According to drawing capacity, steel is divided into deep drawing products and ordinary drawing products. The scope of these cold-rolled products shall comply with GOST 19904.

GOST 9045 specifies the requirements for thin gauge cold rolled materials made of low carbon quality steel, not exceeding 3.9 mm thick, for cold forming. According to the rated characteristics, the products can be classified into 1 to 5 grades, and according to the surface finish quality, the products are classified into type I (super finish), Type II (super finish) and Type III (super finish). Steel is classified into super complex, super complex, complex and deep drawn products based on deep drawing capacity (rolled products up to 2 mm thick). The scope of these cold-rolled products shall comply with GOST 19904.

GOST 17066 describes technical specifications for thin gauge high-strength rolled steel sheets and coils with a thickness of 0.5-3.9 mm and a minimum width of 500 mm. The strength of rolled steel is 295, 315, 345, 355, 390. The shape and dimensional tolerances of cold-rolled steels shall also comply with GOST 19904.

Cold-rolled steel plate production

Cold-rolled sheet can be produced using one of two main methods:

Cut the coil on a dedicated cutter or use a combination cut, then straighten, pack and mark the finished sheet.

Hot rolled sheets are processed in an irreversible cold mill. In this case, the hot rolled steel coil is cut into sheets and used as raw materials. These sheets are processed on pickling lines and then deformed through rollers while still cold to obtain thinner cold-rolled sheets.