Repair welding of polymer injection molds manufactured in AISI P20 and VP50IM steels

The objective of this work was to determine the best practices to repair by welding AISI P20 and VP50IM steels during the manufacturing of polymer injection molds, in such a way to obtain similar characteristics in the weld and base metal, to uniformly respond to the processes of polishing and texturing. The welds by the wire feed TIG process were done using a similar filler metal for P20 steel, AWS A5.28-96 ER 80S-B2, and two filler metals for VP50IM steel, similar and dissimilar AWS A5.28-96 ER 80S-B6. The welds were deposited with different heat inputs (3.6–9.8 kJ/cm), using constant amplitude DC, and they were evaluated in relation to the quality obtained in the mirrored and textured surfaces. Those results were correlated with the chemical compositions, microstructures and hardness.