Efeito da energia de soldagem na zona afetada pelo calor do aço inoxidável ferrítico AISI 444

Abstract

Ferritic stainless steel is susceptible to weld embrittlement when heated during a certain time in 400oC - 550°C temperature interval. This phenomenon increases the material hardness and decreases ductility and corrosion resistance. To weld those kind of materials, it is important to know the problems that might come along in the zone affected by the heat (HAZ). This work intends to caracterize the AISI 444 HAZ, welded with three energy levels using AWS E316L-17 and AWS E309MoL-16 austenitic electrodes. Optical and electron microscopy was performed, and also an assessment of Vickers microhardness through the HAZ. The sow that the AISI 444 HAZ presents significant grain growth and hardness reduction related to the base metal in the region nearer the fusion line. In the same region, it was found a very fine precipitation distribution which could be Laves’ phase.