Difference between cold-galvanized steel pipe and hot-dip galvanized steel pipe

Difference between cold-galvanized steel pipe and hot-dip galvanized steel pipe

Galvanized steel pipe types
Galvanized steel pipe include two kinds:
1. Hot dipped galvanized steel pipe.
2. Cold galvanized pipe, also called electric galvanized pipe.

Galvanized steel pipe sizes and specifications
Nominal diameter (inch): 1/2~4
Nominal wall thickness (mm): 2.0~4.5
Test pressure index: Diameter: 10.2~168.3 mm 3 MPa
Diameter: 177.8~323.9 mm 5 MPa

Cold galvanized steel pipe introduction
Cold galvanized steel pipe is using electric chemical processing coated zinc layer on steel pipe. The zinc layer usually 20~30μm thick.
The zinc content of hot-dip galvanized steel pipes and cold-galvanized steel pipes is very different. Hot-dip galvanizing should not be too small, the double-sided 50 ~ 60g / m2 is generally the smallest, up to 600 grams / square meter. The cold-galvanized steel pipe has a very thin galvanized layer with a minimum of 15 g/m2, but for thicker coatings, the line speed is very slow and does not suit the process characteristics of modern installations, typically up to 100 g/m2.

Manufacturing process of cold galvanized steel pipe:
Degreasing – electroplating – passivation – drying – packaging

Zinc thickness for cold galvanized steel pipe
Cold galvanized steel pipe zinc thickness is 5-15 μm, the layer is dense, and there is no inclusion with organic matter.