Galvanized Steel Pipe

Galvanized Steel pipe is divided into cold galvanized steel pipe, hot galvanized steel pipe,

Hot dip galvanized pipe
The hot-dip galvanized pipe reacts the molten metal with the iron substrate to produce an alloy layer, so that the substrate and the coating are combined. Hot-dip galvanizing is to pickle the steel pipe first. In order to remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to hot-dip coating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot-dip galvanized steel pipe substrate undergoes complex physical and chemical reactions with the molten plating solution to form a corrosion-resistant zinc-iron alloy layer with a tight structure. The alloy layer is integrated with the pure zinc layer and the steel pipe substrate, so it has strong corrosion resistance.
Cold galvanized pipe
Cold galvanized pipe is electro-galvanized, the amount of galvanizing is very small, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. The galvanized pipe manufacturer of the track, in order to ensure the quality, the large purchase of JDG threading pipe does not use electro-galvanizing (cold plating). Only small companies with small equipment and outdated equipment use electro-galvanized steel, of course, their prices are relatively cheaper. The Ministry of Construction has officially laid down the cold-dip galvanized pipes with backward technology, and the cold-dip galvanized pipes are not allowed to be used as water and gas pipes. The galvanized layer of cold-dip galvanized steel pipe is an electroplated layer, and the zinc layer is independently layered with the steel pipe substrate. The zinc layer is relatively thin, and the zinc layer is easily attached to the steel pipe substrate and is easy to fall off. Therefore, its corrosion resistance is poor. In newly built houses, it is forbidden to use cold-galvanized steel pipes as water supply pipes.
weight factor
Nominal wall thickness (mm): 2.0, 2.5, 2.8, 3.2, 3.5, 3.8, 4.0, 4.5.
Coefficient parameters (c): 1.064, 1.051, 1.045, 1.040, 1.036, 1.034, 1.032, 1.028.
Note: The mechanical properties of steel are an important indicator to ensure the final use performance (mechanical properties) of steel, which depends on the chemical composition and heat treatment system of steel. In steel pipe standards, tensile properties (tensile strength, yield strength or yield point, elongation), hardness, toughness, and high and low temperature properties required by users are specified according to different use requirements.
Steel grades: Q215A; Q215B; Q235A; Q235B.
Test pressure value/Mpa: D10.2-168.3mm is 3Mpa; D177.8-323.9mm is 5Mpa
Current national standard
National standard and size standard for galvanized pipe
GB/T3091-2015 Welded steel pipes for low-pressure fluid transportation
GB/T13793-2016 straight seam electric welded steel pipe
GB/T21835-2008 Welded steel pipe dimensions and weight per unit length