Aplicabilidade da técnica da dupla camada para reparo de solda sem TTPS do aço ASTM A335 P91

Abstract

This study sought to evaluate the possibility of applying the welding repair technique known as "Two Bead" in ASTM A335 P91, through the process of Flux Cored Arc Welding (FCAW). For this a basic understanding of this process beyond the theory of repair welding was required. Metallurgical aspects of steel A335 P91 also have been addressed in this study. To conduct the study, weld beads with different welding power were deposited in the P91 steel. The heat affected zone (HAZ) of each bead was evaluated by measuring hardness profiles and measuring the thickness of each subregion by macrograph. Then Higuchi Test was performed to evaluate the use of two bead technique. It was concluded at the end of the work that it would not be possible to apply the technique for the conditions studied, since the region tempered of the beads represented a very small portion of the HAZ. To analyze the behavior of the steel against a heating cycle after it was quenched, a graph comparing the hardness obtained for heating cycles at various temperatures in a residence time of approximately 1 hour was obtained. Indeed, it was noted that the range in which this steel remains with low hardness is very narrow front of the fragile regions. Therefore, it is stated that the two bead technique cannot be applied to steel ASTM A335 P91 for the operating conditions employed in this study.