The results show that there are several reasons for the failure of fusion around the hole wall through several experiments:
(1) No problem with PT and MT flaw indicates that the quality of the surface welding is good, and the quality of the bottom weld is defective. Analysis because the depth of the hole is relatively small diameter (hole 112mm depth, diameter 40mm), the welding hole at the bottom of the gun angle can not be guaranteed, will lead to the hole at the bottom of welding space is insufficient. The torch cannot swing effectively. , resulting in more welding defects at the bottom.
(2) The second batch of specimens shows that the spot shape is less than the first batch, which indicates that the welding quality has been improved. It shows that increasing the operation practice of workers, adopting effective process methods such as preheating, changing welding posture and annealing can effectively reduce welding defects and improve welding quality. In view of the above analysis of the test results. The plug welding process is optimized as follows: The reaming aperture is adjusted by the original diameter of 40mm, extended to diameter 60mm, that is, reducing the depth-width ratio of the hole, and enlarging the swing space of the torch in view of the size limitation of reaming. It is necessary to further improve the welding structure by thinning the hole wall after reaming to produce deformation. Adding the pad in the center of the plug hole can effectively reduce the depth of the hole. The process method is material with the same material as the base material. Processed into smaller than aperture O. 5ram, the thickness of 12mm round gasket, Gasket EDGE processing into 60. The above groove, the workpiece in the form of spot welding in the middle or in the middle of the base. The experiment was carried out according to the improved process method. Analysis of the test results: from the macroscopic analysis and comparison: The hole in the middle of the pad, greatly reducing the difficulty of the plug welding and labor intensity. Improve the production efficiency, reduce the cost, ensure the quality of plug welding from the cross-section corrosion observation: hole in the middle of the pad, welding defects are very small, select reasonable welding parameters. The hole cushion and the mother material all fuse. Can effectively control the defects in the welding process by RT-Ray flaw detection, found that there is no defect. The specimen fully conforms to the welding quality requirement.