Soldagem dissimilar AISI 316L / NiCrMo-3: Efeito do calor aportado sobre as características químicas e geométricas da zona parcialmente misturada

Abstract

Welding of dissimilar materials is used in different industrial sectors to overcome problems in the substrate, such as resistance to degradation in contact with the medium and with the operating condition. However, some combinations of dissimilar alloys show the formation of partially mixed zones (PMZ), which have inferior or different properties than those expected for the weld metal. Thus, this work aims to investigate the influence of heat input and variation in the chemical composition of consumables on the geometric and chemical characteristics of the PMZ. As a welding procedure, AISI 316L alloy was adopted as the base metal. As a consumable, NiCrMo-3 alloy and 100% Ar gas shielding were used. In making the beads, the TIG welding process, in the automated condition, was applied. The results show that the increase in heat input increases the value of Δt8/5 (s), reduces the cooling rate (°C/s) and increases the thickness and changes the hardness of the PMZ. Additionally, the manufacturing conditions adopted influence the chemical composition in the PMZ. Finally, the variation in the chemical composition affects the hardness value in the PMZ, being higher for the condition of lower heat input (H= 0.50 kJ/cm), condition of lower dilution.