The manufacturing process of stainless steel strips is obviously different from that of ordinary cold-rolled strips. That is, the stainless steel strips must undergo an annealing process before cold-rolling, and the surface of the strips must be kept clean at all times during production, so as to increase the number of stainless steel strips. Yield and corrosion resistance of stainless steel strips.

The production process of stainless steel strips is basically hot-rolled strip (blank), annealing, pickling, grinding, cold rolling, annealing, pickling, smoothing, polishing, shearing, inspection and classification to packaging and storage.

The annealing time of ferritic stainless steel and martensitic stainless steel is relatively long, the purpose is to facilitate recrystallization and dissolution of carbides. Generally, annealing is done in a bell-type furnace. The annealing temperature is about 800°C and the temperature is kept for 2 to 6 hours. Ferritic stainless steel must be cooled quickly in air to avoid embrittlement. Martensitic stainless steel must not be cooled rapidly to prevent excessive internal stress and hardening cracks. Austenitic stainless steel is heated to a temperature of 1000 to 1100°C in a continuous furnace and needs to be rapidly cooled in water or air.

The annealed stainless steel strip is first treated by shot blasting. After breaking the surface iron oxide scale, it is brushed and then entered into the pickling tank to completely remove the iron oxide scale and surface passivation. Nitric acid or sulfuric acid is usually used for pickling. The temperature of nitric acid solution is 20 to 55°C, and the temperature of sulfuric acid solution is 50-70°C.

The annealing and pickling of stainless steel strip blanks are usually carried out in the annealing and pickling unit. After the pickled stainless steel strip is inspected, surface defects are repaired on a belt grinder, and then sent to the cold rolling mill for rolling processing.

Stainless steel is a difficult-to-deform steel material and can easily cause work hardening during cold rolling, especially during multi-pass low compression rolling. Stainless steel strips are usually rolled on four-high rolling mills and multi-high rolling mills, such as eight-high rolling mills and twenty-high rolling mills. For austenitic stainless steel that is easier to roll, the compression rate in each pass cannot be greater than 25%, and the total compression rate in each rolling pass cannot be greater than 75%. For martensitic stainless steel with relatively high carbon content, the compression rate per pass is 15%, and the total compression rate per rolling pass is not more than 50%.

When a rolling pass is completed, the cold rolling work hardening is removed by intermediate annealing and pickling. For austenitic stainless steel, the heating temperature reaches 1050-1080°C. For ferritic and martensitic stainless steels, the heating temperature is about 800°C. After heating it is quenched in water, air or steam. The iron sheet formed during the heat treatment is oxidized and loosened in the salt bath furnace, which facilitates pickling.

After pickling, the surface of the stainless steel strip should be inspected and defects should be removed on a grinder. The finished stainless steel strip is bright annealed, which is the last recrystallization annealing in a non-oxidizing atmosphere. Generally, decomposed ammonia is used as protective gas.

After bright annealing, grinding and polishing are usually not performed to ensure the surface roughness of the stainless steel strip obtained. The purpose of smoothing is to optimize the surface quality of the stainless steel strip and also optimize the plate shape of the stainless steel strip. The compression rate when flattened is usually no higher than 2%. In order to obtain a very smooth stainless steel strip surface, the rolls need to be polished frequently during the smoothing process.

In order to enhance the corrosion resistance of stainless steel belts, some special varieties of stainless steel belts need to be ground and polished. Wet grinding is usually used. During grinding, it is necessary to avoid burning spots or cracks caused by the poor thermal conductivity of stainless steel.