The influence of surface treatment process on the performance of ordinary irregular pipes
1. Rust and corrosion resistance performance (core impact)
Black pipe (not handled)
No anti-corrosion ability, easy to rust and oxidize, quickly corroded outdoors, short service life.
Cold galvanizing
Has a certain rust prevention ability, suitable for indoor and dry environments.
hot-dip galvanizing
Extremely strong anti-corrosion, thick zinc layer, good adhesion, preferred for outdoor, humid, and corrosive environments, with a lifespan of several years to over ten years.
Spray painting/spray coating
Beautiful and rust resistant, suitable for furniture, decoration, and indoor structures.
2. Impact on mechanical properties
Cold drawing, cold bending, and heat treatment can improve strength and hardness, but slightly reduce toughness.
The hot-dip galvanizing temperature is not high, and it basically does not affect the strength of the steel pipe.
Improper acid washing can cause hydrogen embrittlement, surface microcracks, and reduce compressive and torsional resistance.
3. Impact on dimensional accuracy and surface quality
Cold galvanizing and spray coating: thin coating, almost unchanged size, high precision.
Hot dip galvanizing: The zinc layer is thicker and the outer diameter will increase, which has a slight impact on assembly accuracy.
Polishing and drawing: Smooth surface, improved aesthetics, and less prone to dust and water accumulation.
4. Impact on welding and processing performance
The galvanized layer can affect the welding quality and easily produce pores and smoke.
Thick zinc layer and plastic powder layer will reduce the smoothness of drilling, punching, and cutting.
Black pipe welding and processing are the most convenient.
5. Regarding service life and environmental adaptability
Hot dip galvanizing>Spray coating>Cold dip galvanizing>Black pipe
Outdoor, rainwater, saline alkali environment: hot-dip galvanizing is required
Indoor, furniture, decoration: sufficient spray/cold coating
Construction machinery and load-bearing structures: Black pipes+most commonly used for later painting
