Surface defects (such as scratches, arc scratches, welding scars, etc.) are inevitable in the process of manufacturing, transportation and construction of stainless steel storage tanks. It only needs to be polished and trimmed, but the thickness of the trimmed steel plate should be greater than or equal to the nominal thickness of the steel plate minus the to allow negative bias values. When the grinding depth is greater than 1mm, welding repair should be carried out.
Before repairing the internal defects of the stainless steel storage tank, the position and depth of the defects should be detected, and the cleaning scope of the exact sink should be determined. . The welded seam after repair shall be inspected according to the specified method and shall meet the qualified standard. The length of the weld bead should not be less than 50mm during rework welding. The number of repairs on the same part should not be more than 2 times, otherwise the general technical person in charge of the construction unit must agree.
For low-alloy steel with σs≥390MPa, penetrant inspection should be carried out after defect treatment to confirm that the defect can be repaired before welding. Temper bead should be used for welding, and after welding, it should be ground and repaired to make the surface of the stainless steel tank smooth and penetrate. Flaw detection or magnetic particle inspection; when the depth of welding defect is greater than 3mm, radiographic inspection should be carried out on the repaired part.
