Aplicabilidade da técnica da dupla camada para reparo de solda sem tratamento térmico pós-soldagem do tubo ASTM A335 P22

Abstract

After welding over ASTM A335 P22 pipes is noted that usually this parts need to be heat treated because the mechanical properties of the heat affected zone (HAZ) are modified. Several times the application of heat treatment to these materials can be unfeasible. Two bead technic can be a good alternative for this problem. This technic can enable projects and make possible a better use of the ASTM A335 P22 pipe. The current work has had as main objective identify the possibility to use two bead technic on ASTM A335 P22 pipe. The welding process utilized for the xperiments was Flux Cored Arc Welding (FCAW). Five beads, each one with a different welding power, were deposited over ASTM A335 P22 pipe and studied. After the deposition of the beads, samples of each one of the beads were withdrawn from the pipe. Two bead technic consists on welding at the same moment that the welding power is strictly controlled during all the welding execution. It is made aiming to generate a tempered region on the rigid region of the previous bead. In order to guarantee that it will happen the criteria of Higuchi Test must be attended. On the current work it was measured the dimensions of the HAZ regions of the five beads previously deposited over ASTM A335 P22 pipe. Finally it was compared the dimensions of the HAZ regions of each bead to verify if the criterion of Higuchi were attended. It was verified that Higuchi criterion were not attended for ASTM A335 P22 pipe. The length of tempered metal region were not long enough compared to the other regions of HAZ.