Research on the Surface Overlay Quality Problems of the Hubs in Axial-Flow Assembling Unit During Ex-Factory Acceptance

The casting material of modified hub in a certain assembling unit was made from 20SiMn Furthermore, it used the puddle welding technology to generate 390L cladding as the surface of hub to improve its anti-cavitation ability. Nevertheless, quality issues were still spotted on the overlay of hubs in ex-factory acceptance. On the one hand, the detecting defects existed in the penetration test; on the other hand, the hardness test was ineligible. After turning off the defective surface, the inner puddle welding layer remained similar defects. Therefore, the surface overlay of hubs was completely turned off and then processed by puddle welding method so as to ensure the overall quality of the hubs.