1.What are the core performance features of DX51D AZ250?
Superior Corrosion Resistance
The aluminum-zinc alloy coating offers 2-6 times the corrosion resistance of ordinary hot-dip galvanized steel (such as DX51D Z275G):
The aluminum forms a dense Al₂O₃ oxide film, preventing the penetration of corrosive media; the zinc provides sacrificial anodic protection. This dual protection mechanism significantly extends service life.
In neutral salt spray testing, AZ250 can withstand 1500-2000 hours without red rust (compared to approximately 300-500 hours for ordinary galvanized Z275G), making it suitable for corrosive environments such as high humidity, coastal areas, and industrial pollution.
Excellent High-Temperature Resistance
The long-term operating temperature can reach 300°C (short-term temperature resistance 600°C), far exceeding the 150°C or lower temperature of ordinary galvanized steel. It can be used in applications near heat sources, such as oven linings, industrial chimneys, and components near automotive exhaust pipes. Excellent Processing Performance
Leveraging the cold-forming advantages of DX51D material, it can be bent (minimum bend radius ≥ 1.5 times the plate thickness), stamped, sheared, and other processes. The coating exhibits strong adhesion and resists peeling or cracking (it can achieve a 0T grade in the T-bend test, meaning it can be bent 180° without peeling).
Unique Surface Properties
The coating exhibits a silvery-white metallic luster, a smooth surface, and high reflectivity (approximately 75%), reducing solar radiation absorption. It is suitable for exterior applications such as roofs and curtain walls, reducing indoor energy consumption.
2.What are the typical application scenarios?
Construction: Roof load-bearing panels, wall panels, light steel keels, canopies, etc., especially suitable for corrosive environments such as coastal areas and industrial zones.
Household appliances and industrial equipment: Oven and microwave oven linings, water heater casings, ventilation ducts, switchgear cabinets, etc., utilizing its high-temperature resistance and corrosion resistance.
Outdoor facilities: Billboard brackets, traffic signal poles, photovoltaic mountings, etc., maintain stability even after long-term exposure to the elements.
3.What are the precautions for use?
Welding: Avoid high temperatures during welding (argon arc welding or resistance welding is recommended), as this may damage localized corrosion resistance.
Cut Protection: Cuts left unprotected by the coating require application of anti-rust paint or sealant, especially in highly corrosive environments.
Avoid contact with dissimilar metals: Direct contact with metals such as copper and iron may cause electrochemical corrosion and requires isolation using insulating gaskets.
4.What is the cold formability performance of DX51D AZ250?
DX51D is constructed from low-carbon steel (carbon content ≤ 0.12%), offering excellent plasticity and ductility, making it suitable for simple to moderate cold forming operations. For example:
Bending: The minimum bend radius can be as low as 1.5 times the sheet thickness (common galvanized sheet typically requires ≥ 2 times), and the coating exhibits no cracking or flaking when bent 180° (passing the T-bend test with a 0T rating, meaning no visible coating flaking after bending).
Stamping: Suitable for shallow drawing and stamping (such as simple curved shapes on appliance housings), but not for deep drawing (because the coating is slightly harder than pure zinc, and excessive stretching may result in localized coating damage).
5.How is the coating adhesion of DX51D AZ250?
The aluminum-zinc alloy coating forms a tight metallurgical bond with the steel substrate, making it less susceptible to peeling or flaking during processing.
The Erichsen test shows a cupping value of 7-9mm (depending on the plate thickness), far exceeding the 5-7mm of standard galvanized steel. This indicates that the coating expands in tandem with deformation of the substrate, reducing the risk of cracking.
It is suitable for machining processes such as shearing and punching, and the coating is less likely to peel off at the cut due to vibration or friction.