What are the requirements for the appearance quality of submerged arc welded steel pipes?
There are strict requirements for the appearance quality of submerged arc welded steel pipes during inspection to ensure the safety of the pipes. The inner and outer surfaces of the steel pipe should be free from visually visible defects such as cracks, folds, scars, rolling and delamination, and these defects should be completely removed, and the removal depth should not exceed the lower deviation of the nominal wall thickness, and the actual wall thickness at the cleaning place should not be less than the minimum allowed by the wall thickness. In addition, there should be no pit with a depth of more than 6.4mm on the surface of the steel pipe, and the length of the pit should not exceed 0.5 times the pipe diameter in any direction. The residual height of the weld should meet the requirements, and the excess part should be grinded to ensure the uniformity and smoothness of the weld. Misalignment, that is, the radial misalignment of both sides of the weld, should not exceed 0.35 times the wall thickness and the maximum should not exceed 3.0mm; for steel pipes with a wall thickness of 13.0mm or less; For steel pipes with wall thickness greater than 13.0mm, the staggered edges should not exceed 0.25 times the wall thickness. The weld itself should have no defects such as cracks, broken arcs, burning through and arc pits, and the shape should be even and smooth with smooth transition. These appearance quality requirements ensure the reliability of submerged arc welded steel pipe in practical application and prevent potential risks caused by appearance defects.
