Q:What are the factors that affect the service life of galvanized profiles?
A:Zinc layer thickness: hot-dip galvanizing (50~100μm+) > cold-dip galvanizing (5~30μm).
Environmental corrosiveness: dry indoor < humid outdoor < coastal / industrial pollution area.
Maintenance measures: regular repainting and removal of corrosion products can extend the service life.
Q:What is the general service life of galvanized profiles under different usage environments?
A:In dry room: hot-dip galvanized profiles for more than 50 years (zinc layer is basically not corroded); cold-dip galvanized profiles for 20~30 years (zinc layer corrodes slowly).
Ordinary outdoor: hot-dip galvanized profiles for 20~50 years (zinc layer is gradually consumed and needs regular inspection); cold-dip galvanized profiles for 5~15 years (zinc layer is thin and prone to red rust).
Humid environment: hot-dip galvanized profiles for 15~30 years (zinc layer accelerates corrosion); cold-dip galvanized profiles for 3~8 years (easy to rust and need frequent maintenance).
Coastal/high salt spray environment: hot-dip galvanized profiles for 10~20 years (chloride ions accelerate zinc layer consumption); cold-dip galvanized profiles for 2~5 years (zinc layer corrodes and perforates quickly).
Industrial acid-base environment: hot-dip galvanized profiles for 5~10 years (zinc layer fails quickly under strong corrosion and requires composite protection); cold-dip galvanized profiles for 1~3 years (not applicable, requires higher protection)
Q:What factors affect the service life of stainless steel?
A:Stainless steel model: 304＜316＜904L and other high alloy models.
Corrosive medium type: Chloride ions (such as seawater) pose the greatest threat to stainless steel, and the scene needs to be distinguished.
Surface integrity: Damage to the passivation film (such as scratches, welding defects) may cause local corrosion.
Q:What is the essential factor that causes the difference in service life between galvanized steel and stainless steel?
A:Galvanized profiles: Rely on consumable coating, life span is directly related to the thickness of zinc layer, the harsher the environment, the shorter life span, and it is irreversible.
Stainless steel: Rely on self-repairing passivation film, life span depends more on the matching degree between alloy composition and environment, reasonable selection can achieve "semi-permanent" corrosion resistance.
Q:What is the impact of maintenance on lifespan?
A：Galvanized profiles: Regular rust removal and re-applying of anti-rust paint can extend the service life by 10 to 20 years (for example, hot-dip galvanizing + anti-corrosion coating on bridges can extend the service life by more than 50 years).
Stainless steel: Generally, no maintenance is required, but in highly polluted environments (such as industrial dust), the surface needs to be cleaned regularly to prevent the passivation film from being damaged by impurities.