Q:What are the requirements for galvanized sheets for car body exterior panels?
A:Coating type: zinc-iron alloy (GA) or hot-dip galvanizing (GI) is preferred.
Thickness requirements: The coating thickness is usually 8-12μm (double-sided galvanizing amount 120-180g/m²), and must pass the neutral salt spray test (NSS) for ≥72 hours without red rust.
Special requirements: The outer panels of high-end models may use zinc-aluminum-magnesium coating (Zn-Al-Mg), with a single-sided coating thickness of ≥5μm, and the corrosion resistance is 3-5 times higher than that of pure zinc.
Q:What are the requirements for galvanized sheets for chassis components?
A:Coating type: hot-dip galvanizing (GI) or zinc-aluminum alloy (ZA).
Thickness requirements: coating thickness 13-25μm (double-sided galvanizing amount 200-375g/m²), must pass acid salt spray test (ASS) ≥1000 hours or cyclic corrosion test (CCT) ≥1200 hours.
Welding requirements: zinc-iron alloy coating (GA) welding spatter rate ≤5%, spot welding current needs to be 10%-20% higher than ordinary steel plate.
Q:What are the requirements for galvanized sheets for structural parts and anti-collision beams?
A:Coating type: hot-dip galvanizing (GI) or zinc-iron alloy (GA).
Thickness requirement: coating thickness 8-15μm (double-sided galvanizing amount 120-225g/m²), high-strength steel with yield strength ≥550MPa (such as DP780) must pass the hole expansion rate ≥40% test.
Q:What type of galvanized sheet is needed for new energy vehicle battery bracket?
A:Coating type: zinc-aluminum-magnesium (Zn-Al-Mg) or zinc-aluminum alloy (ZA).
Thickness requirement: Coating thickness 10-20μm, must pass 2000 hours salt spray test, corrosion rate is only 1/4 of hot-dip galvanizing.
Q:What are the special application scenarios of galvanized sheets in the automotive industry?
A:Commercial vehicle frame: coating thickness ≥ 8μm, tensile strength ≥ 520MPa, in compliance with GB/T 1591-2018 standard.
Vehicles in coastal areas: coating thickness must be ≥ 100μm, and zinc-aluminum-magnesium coating (Zn-Al-Mg) must pass 2000 hours of salt spray test.