The automobile sheet metal material group shall be divided into two categories: Ferrous and nonferrous metal. Due to the performance and price, the consumption of Ferrous accounts for 90% and that of non-ferrous metal only accounts for 10%.
The body sheet metal mainly includes carbon steel, alloy steel, cast iron, non-ferrous metals, and various alloys, non-metallic materials, and composite materials.
The most widely used and basic one is steel plate, which can be classified into low-carbon steel, medium carbon steel, and high carbon steel according to the quality classification discussed. The carbon content in low carbon steel is less than 0.25%, the carbon content in medium carbon steel is between 0.25% -0.6%, and the carbon content in high carbon steel is greater than 0.6%.
At present, most of the sheet metal substrates used by major OEMs are steel plates, and for performance requirements, galvanized steel is often used. There are two main methods for galvanizing steel sheets: hot dip galvanizing and electro galvanizing:
Electro galvanized steel plate (SECC): Uniform gray, mainly imported, fingerprint resistant, with excellent corrosion resistance, and maintains the processability of cold rolled sheet.
Hot dip galvanized steel plate (SGCC): Dipped, bright white, with small zinc flakes. It's actually difficult to see the zinc flakes, but the large zinc flakes can clearly see the hexagonal flower blocks.
Electrogalvanizing and hot-dip galvanizing, with the former having a thinner coating than the latter
Below are specific types of galvanized steel plates:
DX51D+Z-DX57D+Z; DC51D+Z-DC57D+Z
D: Refers to cold formed flat steel
X: Indicates hot rolling method C: cold rolling method
51-57: The larger the number, the better the stamping performance
D: Denotes galvanization
Z: Pure zinc plating
H300LAD+Z: Low alloy high-strength steel
H340LAD+Z: Cold formed high-strength steel
H380LAD+Z: Galvanized coil
22MnB5: pickling Thermoforming high strength steel
The substrate used for each part of the vehicle body varies depending on performance requirements. For example, the side panel, as the largest stamping component in the body system, mostly uses DX54D+Z, with a plastic yield strength between 280-340Mpa; However, automotive safety components such as car door anti-collision beams and reinforcement plates, windshield pillar reinforcement plates, etc., typically use 22MnB5 with a plastic yield strength between 560-690Mpa due to the need for both high strength and good toughness.