Which repair process is best suited for hot runner thermal shock cracking?

Based on our previous discussion on the feasibility and life after repair of hot runner thermal shock cracking repair, argon arc welding (argon arc welding) combined with overall stress-relief heat treatment is the most suitable repair solution, especially for non-penetrating shallow microcracks:

Firstly, the fracture region is ground and cleaned to eliminate the crack extension layer, so as to avoid further development of residual microcracks.

Reduce the accumulation of welding stress, repair the fracture layer by layer with welding wire of hot runner substrate material of low-current low-heat-input argon arc welding.

After welding the whole workpiece shall be put into a furnace for stress-relieving heat treatment at 600-650℃ for 2-3 hours so as to eliminate the residual welding stress completely.

Finally grind and polish the weld region and undertake a dye penetrant inspection to be sure no new microcrack has been created.

This procedure minimizes following cracking, is ideal for the high temperature conditions of hot runners, and is only applicable to small cracks that do not enter the runner, deep cracks are not worth fixing.