Q:What are the international mainstream standards and model systems for aluminum galvanizing?
A:1. China National Standard (GB/T 14978 / GB/T 14977) The coating composition is 55% aluminum + 43.4% zinc + 1.6% silicon (typical aluminum-zinc alloy, corrosion resistance is better than pure zinc plating), and the model number is marked with "GL" for the coating.
2. European Standard (EN 10346) "ZAL" indicates aluminum-zinc alloy coating, and the model structure is "substrate type + coating identification".
3. American Standard (ASTM A792 / A924) "G" indicates coating weight (unit: oz/ft², 1oz≈31g/m²), and the composition is fixed at 55%Al-43.4%Zn-1.6%Si.
4. Japanese Standard (JIS G3321) "GAL" indicates aluminum-zinc alloy coating, and the model number is such as: SGAL40
Q:What are the key parameters for selecting aluminum galvanized models?
A:Coating composition: Traditional aluminum galvanizing is fixed at 55%Al-43.4%Zn-1.6%Si (strong weather resistance, suitable for outdoor use); zinc-aluminum-magnesium alloy (low aluminum) focuses on corrosion resistance and weldability, and needs to be selected according to the environment.
Coating weight: Indoor/light corrosion: 100-150g/m² (double-sided); Outdoor/coastal: 200-275g/m².
Mechanical properties: For ordinary molding, select DX51D+ZAL (yield strength ≈220MPa); For high-strength structure, select HX350LAD+ZAL (yield strength ≥350MPa, used for automotive beams and brackets).
Q:Taking A653 as an example, what do each symbol represent?
A:ASTM A653 is the standard specification for galvanized steel sheets in the United States. The symbols in the model names represent the material type, strength grade and coating requirements.
A: Represents the steel material category in the ASTM standard (such as A36, A572, etc.).
653: The serial number of the standard, corresponding to the specific specifications of "hot-dip galvanized or zinc-iron alloy coated thin steel sheet"
Q:What should you pay attention to when choosing a model?
A:1. Coating weight and life: The thicker the coating (such as AZ200), the longer the corrosion resistance life (up to 30 years or more), but the cost is higher.
2. Processing adaptability: For deep drawing processing, you need to choose a model with strong coating adhesion.
3. Environmental protection requirements: Some models may contain a chromium passivation layer, and chromium-free passivation must be selected for export.
Q:What is the difference between aluminum galvanized and aluminum plate?
A:Coating composition: Aluminum galvanizing is mainly composed of 55% aluminum, 43.4% zinc, and 1.6% silicon, while galvanized sheet is mainly composed of pure zinc (or zinc-iron alloy containing a small amount of iron).
Corrosion resistance: Aluminum galvanizing is significantly better than galvanized sheet in terms of salt spray and atmospheric corrosion resistance (about 3-6 times) due to the protection of aluminum oxide film, and is suitable for harsh environments such as high humidity and coastal areas.
Processing and application: Galvanized sheet has better weldability and is mostly used in ordinary buildings and home appliances; aluminum galvanizing has high surface hardness and high temperature resistance, and is more suitable for automobile outer panels and outdoor high weather-resistant structural parts.