Sheet Metal Materials Used in Automotive Stamping and Fabrication Include
1. Cold-Rolled Steel (SPCC)
SPCC refers to steel coil or sheet material that is continuously rolled by a cold rolling mill to the desired thickness. The surface of SPCC has no protective coating, making it highly susceptible to oxidation when exposed to air—especially in humid environments, where rusting accelerates, resulting in dark red iron oxide. For practical use, the surface must be painted, electroplated, or otherwise treated for protection.
2. Electrogalvanized Steel (SECC)
SECC is made from standard cold-rolled steel coils that undergo degreasing, acid washing, electroplating, and various post-treatment processes in a continuous electrogalvanizing line to produce an electroplated zinc product.
SECC not only retains the mechanical properties and machinability of regular cold-rolled steel but also offers superior corrosion resistance and an aesthetically pleasing finish. It is highly competitive and often used as a substitute in markets such as electronics, home appliances, and furniture. For example, computer cases commonly use SECC.
3. Hot-Dip Galvanized Steel (SGCC)
Hot-dip galvanized steel coils are produced by cleaning and annealing hot-rolled pickled or cold-rolled semi-finished products, then immersing them in a molten zinc bath at approximately 460°C to coat the steel with a zinc layer. Afterward, the material undergoes temper rolling, leveling, and chemical treatment.
Compared to SECC, SGCC is harder with poorer ductility (avoiding deep drawing designs), has a thicker zinc coating, and exhibits poorer weldability.
4. Stainless Steel SUS301
SUS301 has a lower chromium (Cr) content than SUS304, resulting in weaker corrosion resistance. However, it achieves excellent tensile strength and hardness through cold working, along with good elasticity. It is commonly used in spring plates, springs, and EMI shielding applications.
5. Stainless Steel SUS304
One of the most widely used stainless steels, SUS304 contains nickel (Ni), giving it better corrosion and heat resistance compared to chromium (Cr)-based steels. It offers superior mechanical properties without hardening from heat treatment and lacks elasticity.