Quality requirements for cold-rolled automotive sheets

Generally, the automobile industry has the following requirements for the cold-rolled steel plates used: 1) Excellent formability, namely: high plastic strain ratio r value, high uniform elongation δu, high total elongation δt, low yield strength σs, low aging index AI and low yield elongation , used for stamping complex automobile panels. 2) Excellent dent resistance and sufficient structural rigidity to avoid dents during manufacturing and use, especially in sudden collision accidents, to maximize energy absorption and protect the safety of the occupants.

3) Good welding performance to ensure effective connection of parts and no major changes in the strength and performance of the solder joints and areas surrounding the solder joints.

4) Excellent surface morphology and smoothness, good spraying performance and adhesion to paint coating, in order to achieve a beautiful surface.

5) High corrosion resistance.

6) Good plate shape and surface flatness, strict dimensional accuracy and performance uniformity.

7) Good sound absorption and vibration damping properties, used in some parts to reduce the thunder effect of the car while driving. Due to these special quality requirements of cold-rolled automobile sheets, the production process is complex and difficult. Therefore, the manufacturers of automobile sheets have adopted the principle of consistent production in actual production, that is, smelting, continuous casting, hot rolling, cold rolling, and annealing. and coating and plating and other processes involved in unified production planning and management.