Estudo do processo de cladding por soldagem TIG pulsado em aço ferramenta TENAX300 [marca registrada]

Abstract

The growing demand for parts manufactured by aluminum die-casting, driven by the automotive industry, directly influences the constant improvement of the molds and dies industry. On the other hand, due to the high thermomechanical stresses present in the mold walls, it is common to find failures and cracks on the surface, requiring frequent repair in the affected region. This procedure is performed by various techniques, however, the most commonly used is still the cladding process deposited by TIG welding. In this study, coatings deposited by Pulsed TIG were investigated, using 1.2 mm wire of H13 on TENAX300 [trade mark] steel. This material is manufactured by Villares SA and aims to withstand thermal fatigue and mechanical stresses caused by injection cycles, presenting greater toughness. Microstructural changes, hardness and toughness of the cladding region and CGHAZ were studied. Based on the results obtained, it was concluded that the cladding process deposited by Pulsed TIG using H13 wire on TENAX300 [trade mark] steel is feasible for proper filling of the substrate samples' bevel. The application of preheating and interpass temperature control influenced phase transformations and hardness in the HAZ and CGHAZ. Although the impact resistance of the TIG-P cladding was lower than that of the TENAX300 [trade mark] substrate, the values obtained for the heat-affected zone were higher than those specified by the NADCA standard. It was concluded that the stress relief heat treatment (TTAT) was not adequate to increase the toughness of the cladding zone and that the CGHAZ was the region with the highest hardness.