WELD CRACK RECTIFICATION IN CATALYTIC CONVERTER BY FABRICATION OF CUSTOMIZED JIG PLATES

The main objective of this paper is to “rectify the weld cracks by the fabrication of customized jig plates”. In the engine section of the industry, there were frequent rejections of the catalytic converters due to weld cracks. When the catalytic converter assembly line was inspected, tiny cracks in the weld were found vi sually. Then they were tested through bench magnifiers and dye penetration test for confirmation and it was confirmed to have cracks in the weld. The crack was found in the casting to shell joint of the catalytic converter. Then the casting was tested for its contaminants which could also cause cracks in the weld. The DED (double end drive) welding jig plate setup was also checked thoroughly for any defects. In order to check whether the type of welding used gives better penetration and strength, wel d penet ration test was done. Finally, after several inspections of the welding process it was found that the crack was due to the biasing of the axis of jig plates. Then, finally the biasing was avoided by fabricating a new jig plate. Thus the entire defect is dr astically reduced by minimizing the cracks and thus maintaining the efficiency of the engine.