Hot-dip galvanized steel pipes are widely used in various manufacturing industries such as construction, machinery, coal mining, chemical engineering, electric power, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, mining machinery, greenhouse construction, and more.

Galvanized steel pipes are welded steel pipes with a hot-dip galvanized or electroplated zinc coating on their surface. Galvanizing enhances the corrosion resistance of steel pipes and prolongs their service life. Galvanized pipes have a wide range of applications. Besides serving as pipeline pipes for general low-pressure fluids such as water, gas, and oil, they are also used in the petroleum industry, especially in offshore oil fields as oil well pipes and oil pipelines, in chemical coking equipment as tubes for oil heaters, condensers, and coal distillation wash oil exchangers, as well as in trestle pipe piles and support frames for mine tunnels.

Hot-dip galvanizing involves reacting molten metal with the iron substrate to form an alloy layer, thereby combining the substrate and the coating. The process begins with acid pickling of the steel pipe to remove iron oxides on its surface. After acid pickling, the pipe is cleaned in a tank containing an aqueous solution of ammonium chloride or zinc chloride, or a mixture of both, and then sent to the hot dip galvanizing tank. Hot-dip galvanizing offers advantages such as uniform coating, strong adhesion, and long service life. The substrate of the hot-dip galvanized steel pipe undergoes complex physical and chemical reactions with the molten coating solution, forming a corrosion-resistant and tightly structured zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe substrate, thus providing strong corrosion resistance.

Cold-dip galvanized pipe

Cold-dip galvanized pipe refers to electro-galvanized pipe, with a very small amount of zinc coating, only 10-50g/m2. Its corrosion resistance is significantly inferior to that of hot-dip galvanized pipe. Most reputable galvanized pipe manufacturers avoid using electro-galvanizing (cold-dip galvanizing) to ensure quality. Only small-scale, outdated equipment enterprises use electro-galvanizing, and their prices are naturally lower. The Ministry of Construction has officially issued a directive to phase out technologically outdated cold-dip galvanized pipes and prohibit their use as water and gas pipes. The galvanized layer of cold-dip galvanized steel pipes is an electroplated layer, which is separately layered from the steel pipe substrate. The zinc layer is relatively thin and simply adheres to the steel pipe substrate, making it prone to detachment. Therefore, its corrosion resistance is poor. In newly constructed residential buildings, the use of cold-dip galvanized steel pipes as water supply pipes is prohibited.

weight coefficient

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.

Steel grades: Q215A; Q215B; Q235A; Q235B.

Test pressure value/Mpa: 3Mpa for D10.2-168.3mm; 5Mpa for D177.8-323.9mm