Introduction to hot-dip galvanized pipes

Welded steel pipes with hot-dip or electro-galvanized layers on the surface. Galvanizing can increase the corrosion resistance of steel pipes and extend their service life. Galvanized Pipes are widely used. In addition to being used as pipeline pipes for general low-pressure fluids such as water, gas, and oil, they are also used as oil well pipes and oil pipelines in the petroleum industry, especially offshore oil fields, and as oil heaters and condensators in chemical coking equipment. Pipes for coolers, coal distillate wash oil exchangers, pipes for trestle pipe piles, and support frames for mine tunnels, etc.
Hot-dip galvanizing pipe reacts molten metal with an iron matrix to produce an alloy layer, thereby combining the matrix and the coating. 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 in an aqueous solution of ammonium chloride or zinc chloride or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to in a hot dip plating tank.

Hot-dip Galvanized Steel Pipe has the advantages of uniform coating, strong adhesion, and long service life. The steel pipe matrix undergoes complex physical and chemical reactions with the molten plating bath 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 matrix. Therefore, it has strong corrosion resistance.
Surface quality of Galvanized Steel pipes
1. Uniformity of the galvanized layer: The steel pipe sample shall not turn red (copper-plated color) after being immersed in copper sulfate solution for 5 consecutive times.

2. Surface quality: The surface of galvanized steel pipes should have a complete galvanized layer. There should be no uncoated black spots and bubbles. Small rough surfaces and local zinc tumors are allowed.

3. Galvanized layer weight: According to the requirements of the purchaser, galvanized steel pipes can be measured for zinc layer weight. The average value should not be less than 500g/square meter, and any sample should not be less than 480g/square meter.