Auto body steel

Steel plate for car body

01The main properties of steel plates are: plasticity, elasticity, work hardening, etc.;
Hot-rolled mild steel plate: The carbon content is generally less than 0.15%, the hardness is low, and the tensile strength is not high. Mainly used for fenders, floors, trunk hinges, bumpers, etc.
Cold-rolled mild steel plate: Compared with hot-rolled mild steel plate, it has better processing performance and beautiful surface. Such as Q215, carbon steel and low alloy structural steel cold-rolled steel plates, 10F, 08F, high-quality carbon structural steel cold-rolled thin steel plates, etc., used for body outer panels, parts shells, roof panels, trunk lids, engine hoods, etc. Door inner and outer panels, bumpers, fenders, etc.
High-strength steel plate: The tensile strength is quite high and it has strong resistance to damage. Used for body outer panels, fenders, etc.
Surface-treated steel: galvanized steel plate, zinc powder paint-coated steel plate, etc., with good anti-corrosion performance. Used for doors, roof linings, lower fenders, underbody, etc. Automobile body steel (category 3)

02 Steel for automobile body outer panels:
Steel for automobile body outer panels is mainly used to manufacture front, rear, left and right door outer panels, hood outer panels, trunk lid outer panels and other parts. Automobile body outer panels should have good formability, corrosion resistance and dent resistance as well as good spot weldability. Automobile body outer panels mostly use plated sheets to meet the anti-corrosion requirements of automobile outer panels running for 4 years without rust spots (recently in Europe Higher anti-corrosion requirements have been put forward, that is, the anti-corrosion performance of the outer panel has the same life span as that of the automobile). In order to improve the dent resistance, the steel plates of automobile outer panels are mostly made of BH steel (bake hardened steel), IF phosphorus-increased steel and high formability. Cold-rolled annealed dual-phase steel (such as DP30260, etc.) to reduce thickness and ensure dent resistance; coated panels are mostly made of hot-dip galvanized sheets, hot-dip galvanized iron sheets, electro-galvanized sheets and electro-galvanized-Ni sheets, etc., with alloy coating The purpose of the plate is to thin the coating thickness, improve the bonding force, improve spot weldability, and reduce zinc pollution in the welding workshop. Steel for inner panels of automobile bodies (steel for inner panels of four doors and two covers):
The shape of the inner panel parts of the automobile body is more complex than that of the outer panel. The steel used for the inner panel of the automobile body is required to have higher formability and deep drawing performance. Therefore, IF steel with excellent stamping formability and deep drawing performance is mostly used for the inner body panel, and a small amount is used. IF - phosphorus-enhanced steel; its coating requirements are similar to those of the outer plate, hot-dip Zn2Fe plate or electroplated Zn2Ni plate; because the alloy coating is thin, in order to prevent damage to the coating during transportation or stamping, it is usually coated with another layer on the surface of the plate. A layer of organic film not only protects the coating, but also improves stamping performance, reduces stamping friction and coating damage, and improves sheet formability.

Steel for automobile body structural parts—advanced high-strength steel:
The main types of high-strength steel plates include: solid solution strengthening type with addition of Si, Mn, P, etc.; precipitation hardening type with addition of Nb, Ti, V, etc.; composite structure type, duplex type and recovery annealing type, etc. The tensile strength of high-strength steel plates is generally above 600N/mm2, and its failure strength is 2 to 3 times that of low-carbon steel plates. Body structural parts or body-in-white (BIW) are not only related to automobile collision safety, but also closely related to automobile lightweight; therefore, the material selection requires both high strength and good plasticity. Advanced high strength steel (AHSS) has better strain distribution ability and higher strain hardening characteristics, and its mechanical properties are more uniform, so its rebound amount has small fluctuations; at the same time, this type of steel has better Collision characteristics and higher fatigue life; therefore, using this type of steel has more possibilities to reduce plate thickness and thin specifications.