In order to improve the corrosion resistance of the steel pipe, the general steel pipe is galvanized.
1. Galvanized steel pipes are divided into hot-dip galvanizing and electro-galvanizing. The hot-dip galvanizing layer is thick, the cost of electro-galvanizing is low, and the surface is not very smooth.
2. Nominal wall thickness(mm): 2.0, 2.5, 2.8, 3.2, 3.5, 3.8, 4.0, 4.5;
3. Coefficients(c): 1.064, 1.051, 1.045, 1.040, 1.036, 1.034, 1.032, 1.028.
Note: The mechanical properties of steel is an important index to ensure the final use performance (mechanical properties) of the steel, and it depends on the chemical composition of the steel and the heat treatment system. In the steel pipe standard, according to different application requirements, the tensile properties (tensile strength, yield strength or yield point, elongation), hardness, toughness indexes, and high and low temperature properties required by users are specified.
1. Grades of galvanized pipe steel: Q215A; Q215B; Q235A; Q235B;
2. Test pressure value/Mpa: D10.2-168.3mm is 3Mpa; D177.8-323.9mm is 5Mpa.
Galvanized steel pipes are divided into cold galvanized pipes and hot-dip galvanized steel pipes. The former has been banned, while the latter is also promoted by the state.
1. The 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 the galvanized steel pipe should have a complete galvanized layer, and there must be no unplated black spots and bubbles, and small rough surfaces and local zinc tumors are allowed.
3. Galvanized layer weight: According to the requirements of the buyer, the galvanized steel pipe can be used to determine the weight of the zinc layer. The average value should not be less than 500g/square meter, and any sample must not be less than 480g/square meter.