process performance inspection:
1. Bending test: Bending test should be carried out on steel tubes with an outer diameter less than or equal to 50mm. The bending angle is 90°, the bending radius is equal to 6 times the outer diameter of the tube. The weld is located at the outermost part of the bend. Defects such as fracture openings.
2. Flattening test: 50mm long steel pipe is taken as a sample, and the distance between the two pressing plates is compressed to 213 of the outer diameter of the steel pipe. The weld position should be at an angle of 90° with the direction of the force. There will be no cracks or cracks after flattening. Weld cracking is qualified.
3. Hydrostatic test: Fill the pipe with water so that it can withstand the specified test pressure within a certain period of time, and no leakage of water can occur. Ordinary steel pipe -0.25 Mpa, thick steel pipe -3.0 Mpa.
4. Surface quality of steel pipe:
a. The outer surface of the steel pipe must be free from harmful defects such as cracks, scars, indentations and deep scribes, etc., but indentations that do not exceed the negative bias of the wall thickness are allowed. Weld misalignment, overlap welding, Defects such as burns and excessive burrs at the wound.
b. The wall thickness of the weld on the inner surface of the pipe is allowed to be thickened and the burr of the welding bead is slightly present. The burr inside and outside the cut is not more than 0.5 mm.