Inspection method of galvanized pipe

　　1 surface inspection

　　The inner and outer surfaces of galvanized steel pipes shall be inspected with the naked eye, one by one.

　　2 size check

　　The galvanized steel pipe should be tested on a black tube before galvanizing with a child equipment with sufficient accuracy.

　　3 thread inspection

　　Threaded galvanized steel pipe, according to YB 822 regulations, use a ring gauge to check the thread one by one.

　　4 Other inspections

　　(1) Galvanization guide uniformity test; test method: "copper sulfate impregnation method for homogeneity test of galvanized layer";

　　Sampling location and miles: Take 2 steel pipes for each batch, and take 1 longitudinal sample.

　　Cold bending test; Test method: GB244; Sampling location and several miles: Take 1 steel pipe for each batch, and take 1 longitudinal sample for each.

　　(3) Determination of weight of galvanized layer; Test method: "Measurement of weight of galvanized layer by antimony chloride method";

　　Sampling location and miles: Take 2 steel pipes for each batch, and take 1 longitudinal sample.