Standard corrosion resistance grade: The zinc coating thickness is approximately 60μm. It provides good corrosion protection in general atmospheric environments and mildly corrosive media, and can be used for several years.

Medium corrosion resistance grade: The zinc coating thickness is approximately 85μm. It has good corrosion resistance in harsher atmospheric environments, industrial pollution environments, or mildly corrosive chemical media, and its service life can reach approximately 10 to 15 years.

High corrosion resistance grade: The zinc coating thickness reaches 125μm and above. This type of hot-dip galvanized square tube provides excellent corrosion protection in extremely harsh corrosive environments, such as high humidity, high salinity, and strong acid/alkali environments, and its service life can exceed 20 years or even longer.

Time：13/05/2026 17:18:39

The corrosion resistance of hot-dip galvanized pipes mainly depends on the zinc layer thickness and process quality. Internationally accepted grading standards are based on the zinc layer's unit area weight (g/m²) and microstructure:
Level 1 (Standard): Zinc layer thickness 85-120μm (600-900g/m²), using pure zinc coating, suitable for ordinary inland atmospheric environments, with an expected lifespan of 15-20 years.
Level 2 (Reinforced): Zinc layer 120-200μm (900-1500g/m²), with the addition of 0.3%-0.6% aluminum to form a Zn-Al alloy layer, improving weather resistance by 30%, suitable for high-humidity coastal areas.
Level 3 (Heavy-Duty): Zinc layer ≥200μm (above 1500g/m²), using a hot-spray zinc coating + sealed coating composite process, with salt spray resistance exceeding 5000 hours, suitable for C5-level corrosive environments such as chemical plants and offshore platforms.
Level 4 corrosion protection (special grade): Based on Level 3, an epoxy coal tar pitch or PE coating is added to form a dual protection system of "zinc layer + organic coating", and the service life of buried pipelines can reach 50 years.

Time：11/05/2026 11:14:14

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