|
Comparison Dimensions |
Galvanized pipe |
Black steel pipe |
|
Anti-corrosion mechanism |
Sacrificial anode protection (zinc layer preferentially oxidized) |
Reliance on iron oxide passivation layer |
|
Salt spray life |
2000 hours without red rust |
Red rust appears after 72 hours |
|
Coating Thickness |
80-120μm (hot dip galvanized) |
No coating, oxide layer ≤ 5μm |
|
Initial Cost |
¥42.8/m (including galvanizing process) |
¥28.5/m (basic material) |
|
Service life |
25 years+ (ISO 9227 certified) |
5-8 years (humid environment) |
|
Pressure bearing capacity |
28MPa (Zinc layer reduces strength) |
32MPa (thick wall pipe) |
|
Welding Limitations |
Welding is prohibited (damage to zinc layer) |
Support arc welding/TIG welding |
|
Applicable environment |
pH 3-11, chloride ion＞500ppm |
Dry environment with humidity less than 60% |
|
Maintenance Requirements |
No active maintenance required (self-healing) |
Apply anti-rust paint every 2 years |
|
Weight Difference |
Increase 4-7% (zinc coating weight) |
Base weight (no additional layers) |
