Supply galvanized steel pipe Promotions Price
Supply galvanized steel pipe Promotions Price
Technical requirements for galvanized steel pipe
1. Grade and chemical composition
The grade and chemical composition of the steel used for galvanized steel pipes shall comply with the grade and chemical composition of steel used for black pipes as specified in GB / T3092.
2. Manufacturing method
The manufacturing method of the black tube (furnace welding or electric welding) is selected by the manufacturer. Galvanizing uses hot-dip galvanizing.
3.Threads and pipe joints
a: For galvanized steel pipes delivered with threads, the threads should be turned after galvanizing. The threads shall comply with the provisions of YB 822.
b: Steel pipe joints shall comply with YB 238; malleable cast iron pipe joints shall comply with YB 230.
4. Mechanical properties The mechanical properties of steel pipes before galvanizing shall meet the requirements of GB 3092.
5. Uniformity of galvanized layer Galvanized steel pipe shall be used for the test of uniformity of galvanized layer. The steel pipe sample must not be reddened (copper-plated) for 5 consecutive immersions in the copper sulfate solution.
6. Cold bending test Galvanized steel pipes with a nominal diameter of not more than 50mm should be subjected to cold bending test. The bending angle is 90 °, and the bending radius is 8 times the outer diameter. The test shall be carried without filler, and the weld of the test specimen shall be placed outside or above the bending direction. After the test, there should be no cracks or zinc peeling on the sample.
7. Hydraulic pressure test The hydraulic pressure test should be carried out in a black tube. Eddy current flaw detection can also be used instead of the hydraulic pressure test. The test pressure or eddy current inspection comparison specimen size shall meet the requirements of GB 3092. The mechanical properties of steel are important indicators to ensure the end-use performance (mechanical properties) of the steel.