Stainless steel sheets are mainly hot-rolled and cold-rolled. From appearance to application performance, the difference between the two is very obvious.

Cold rolling and hot rolling are two different steel rolling technologies. As the name implies, cold rolling is rolling steel at room temperature, and this kind of steel has high hardness. Hot rolling is rolling steel at high temperature.

Hot-rolled stainless steel has a higher temperature of stainless steel rolled parts, low deformation resistance, and can show a larger deformation amount. And because the initial raw material, continuous casting slab or initial rolling slab, has a relatively small width-to-thickness ratio, and the dimensional accuracy requirements are relatively low, it is not easy to cause plate shape problems, and the main thing is to control the convexity. If there are requirements for metal structure, the microstructure and mechanical properties of the stainless steel plate are usually controlled by controlling the start rolling temperature, final rolling temperature and curling temperature of the finishing rolling.

The process of hot rolling is to use continuous casting slab or initial rolling slab as raw material, heat it in a step-beam heating furnace, remove scale with high-pressure water, and then enter the rough rolling mill. The rough rolling material is cut and then enters the finishing mill for computer-controlled rolling. After the final rolling, it is cooled by laminar flow, and the cooling rate is controlled by computer. It is coiled by the coiler to become a straight coil. The head and tail of the straight coil are often tongue-shaped and fishtail-shaped, and the thickness and width accuracy are relatively poor. There are often defects such as wave shape, folded edge, and tower shape on the edge. The coil weight is heavy and the inner diameter of the steel coil is 760m. Generally, the pipe making industry likes to use this kind of steel coil. After the straight coil is cut, cut, trimmed and multiple processes, straightened, flattened and other finishing treatments are carried out, and then cut or re-rolled, it becomes: hot-rolled steel plate, flat hot-rolled steel coil, longitudinally cut strip and other products. If the hot-rolled finishing coil is pickled, the oxide scale is removed, and it is oiled, it becomes a hot-rolled pickled coil. This product has a tendency to partially replace cold-rolled stainless steel plates, and the price is moderate, so it is deeply loved by the majority of users.

Cold rolling usually does not have a heating process before rolling. However, because the thickness of stainless steel plates is small, it is easier to produce plate shape problems. In addition, most of the products after cold rolling are finished products, so in order to control the dimensional accuracy and surface quality of stainless steel plates, complex production processes will be used. The cold rolling production line is long, the equipment is large, and the process is very complicated.

Cold rolling uses hot-rolled steel coils as raw materials. After pickling and removing the oxide scale, cold continuous rolling is carried out. The finished product is hard-rolled coils. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the hard-rolled coils increase, and the toughness and plasticity index decrease. Therefore, the stamping performance will deteriorate and can only be used for parts with simple deformation. Hard-rolled coils can be used as raw materials for hot-dip galvanizing plants, because hot-dip galvanizing units are equipped with annealing lines. The weight of hard-rolled coils is generally 6~13.5 tons, and the inner diameter of the steel coil is 610mm.

Usually, cold-rolled plates and cold-rolled coils should be subjected to continuous annealing (CAPL unit) or bell furnace annealing to eliminate cold work hardening and rolling stress, and meet the corresponding standard mechanical performance indicators. The surface quality, appearance, and dimensional accuracy of cold-rolled steel plates are better than those of hot-rolled plates, and the thickness of its products can be rolled to about 0.18m, which is favored by the majority of users. The deep processing of products with cold-rolled steel coils as substrates has become a high value-added product. Such as electrogalvanizing, hot-dip galvanizing, fingerprint-resistant electrogalvanizing, color-coated steel coils, vibration-damping composite steel plates, and PVC laminated steel plates.

The appearance difference between cold-rolled stainless steel and hot-rolled stainless steel is also obvious, and the surface of cold-rolled stainless steel plates has a good glossiness. If the hot-rolled stainless steel plate is not pickled, it is similar to the surface of many ordinary steel plates on the market. The rusted surface is red, and the unrusted surface is purple-black.

The performance advantage of cold-rolled stainless steel plates over hot-rolled stainless steel plates is mainly higher precision, and the thickness difference of cold rolling does not exceed 0.01~0.03m. The size of cold-rolled stainless steel can be thinner. The thinnest cold-rolled steel strip can be 0.001mm; the thinnest hot-rolled steel strip can now reach 0.78mm. The surface quality of cold-rolled stainless steel is better. Cold-rolled stainless steel sheets can even produce mirror surfaces, but hot-rolled stainless steel sheets will have defects such as iron oxide scale and pitting on their surfaces. Cold-rolled stainless steel sheets can adjust their mechanical properties according to user requirements.