Before the straight seam steel pipe is not tested, the appearance inspection of the weld should meet the requirements. The welding joint for tube joints generally requires the appearance and surface quality of direct welding seams as follows:
The welding shape should be good, and the width should be covered by 2mm on both sides of the ramp. The height of the welding joint of corner welding should meet the design regulations, and the shape should be transitioned smoothly.
Welding joint surface
(1) No cracks are allowed, no melting, residue, and splashing.
(2) Steel pipes with a design temperature lower than-29 degrees, and the weld surface of stainless steel steel pipes with a large tendency of hardening shall not bite the side. The weld bite of other related materials should be greater than 0.5 mm. The length of the continuous side should not use more than 100 mm. The total length of the bite side on both sides of the weld should not exceed 10 % of the total length of the weld.
(3) The surface of the weld must not be lower than the surface of the pipeline. High welding residual amount is not greater than 3mm.
(4) The wrong edges of the welding connector should not exceed 10 % of the wall thickness, and should not exceed 2mm.
