Cause analysis of transverse breakage of ultra high-strength steel shell after hydraulic blasting test

To ensure product quality, the inspection and analysis were carried out on the ultra high-strength steel welded shell with transverse rupture after qualified hydraulic blasting test. Firstly, we carried out spot investigation of hydraulic blasting test, breakage morphological analysis, investigation on production technology, reexamination of wall-thickness and X-ray film of welding joint; in case of different opinions on fast analysis, then, we carried out contrast detection and analysis on stripe of fracture, metallographic analysis on cross section of welding joint, TEM detection and analysis on fracture, and inspection and analysis on welding size and offset. The analysis results showed that, the transverse rupture of test sample after hydraulic blasting test was caused by the failure of part incomplete joint penetration on welding joint, which was due to welding arc deviation. Therefore, with the improvements of welding equipments, tooling and operation methods to prevent radial and weld offset, the welding quality was assured and improved.