LPG tank weld inspection
(3) Level of residual stress in the weld
The existence of residual stress will strengthen the tensile stress environment, and stress corrosion cracks generally appear in welds with high welding residual stress. Post-weld heat treatment can significantly reduce the tendency of stress corrosion. The residual stress of the weld can be measured through residual stress testing, and the heat treatment status of the weld can also be judged through the weld hardness test.
To detect stress corrosion cracks, an effective way is to perform fluorescent magnetic particle inspection on the inner surface of the storage tank. Practice has proven that the crack detection rate is very high. It can also be combined with metallographic inspection to determine the nature of the crack and the presence of stress corrosion micro-cracks. .
