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How to distinguish stainless steel plate, coil, pipe and profile hot rolling and cold rolling process?

How to distinguish stainless steel plate, coil, pipe and profile hot rolling and cold rolling process?

Time:2022-03-16 Source:WUXI JIANO SPECIAL STEEL CO.

How to distinguish stainless steel hot rolling and cold rolling process? The following is introduced to you by Wuxi JIANO Special Steel. Hot rolling and cold rolling are both forming process of section steel or steel plate, which has great influence on the organization and performance of steel. Hot rolling is the main rolling process of steel, while cold rolling is only used to produce small sections and thin plates.

Steelmaking process: iron (alloy, scrap) → slagging (debris removal) → electric furnace refining (reduction of sulfur, phosphorus, silicon) → reduction of carbon, nitrogen components → AOD / VOD (continuous control of C, N and other elements) → continuous casting billet

Stainless steel hot rolling process

The hot rolling process of stainless steel is based on slabs (mainly continuous cast slabs) as raw material. The strip is heated and then produced by roughing and finishing mills. The hot rolled strip from a finishing mill is cooled to a set temperature by laminar flow and then rolled into coils by a coiler. After cooling, the surface of the steel coil has oxide skin, black, commonly known as “stainless steel black skin coil”. After annealing and pickling, the oxidized surface is removed, which is called “stainless steel white skin coil”. Most of the hot rolled products in the stainless steel market are stainless steel white skin coils.

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Stainless Steel Cold Rolling Process

After stainless steel hot rolling, some hot rolled stainless steel products are used directly downstream, and some hot rolled stainless steel products need to be processed into cold rolled products before use. Stainless steel cold rolling, most of the hot-rolled thickness of 3.0-5.5mm stainless steel hot-rolled products, by cold rolling equipment calendering process, the production of stainless steel cold rolled products. At present, there are two main production processes for stainless steel cold rolling: single-stand cold rolling and multi-stand cold rolling.

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Stainless steel cold-rolled requires annealing pickling line. The annealing of cold rolled stainless steel is to eliminate process hardening through recrystallization to achieve the purpose of softening; the purpose of pickling is to remove the oxide layer formed on the surface of the strip during the annealing process, passivate the surface of stainless steel and improve the corrosion resistance of the steel plate.

There are many steel mill specifications, and annealing and pickling are subdivided into oxidation annealing (2b) and bright annealing (BA). There are many subsequent processes for cold rolling.

The main differences between hot-rolled and cold-rolled are as follows.

1, cold-rolled sections allow local buckling, which can make full use of the load-bearing capacity after buckling; hot-rolled sections do not allow local buckling.

2, hot-rolled sections and cold-rolled sections produce residual stress for different reasons, so the distribution of residual stress in the section is also different. The residual stress distribution of cold-formed thin-walled sections is bending type, and the residual stress distribution of hot-rolled or welded sections is film type.

3, the free torsional stiffness of hot-rolled sections is higher than that of cold-rolled sections, so the torsional resistance of hot-rolled sections is better than that of cold-rolled sections