Investigação metalográfica da zona afetada pelo calor da estrutura soldada de aço maraging com AISI 8630 modificado

Abstract

The welding of dissimilar joints is very common in systems used in oil exploration and production in deep waters. Commonly involves welding low carbon steel pipes with low alloy forged steel, more often, with cladding of Inconel. An alternative technique for reducing residual stresses is to use a filling material that during the cooling process undergoes a displacive transformation at a relatively low temperature so that the deformation resulting from the transformation compensates the contraction during the cooling process. Thus, the aim of this study is to evaluate the use of maraging 250 (Mar 250) as weld metal in dissimilar union of materials applied in the oil industry. It has been used samples of structural steels in mid-v and welded using welding rods. The levels of residual stress and microstructure of the heat-affected zone (HAZ) were investigated not only in the joint welded with Mar 250 but also in a joint welded with a conventional filler metal. An important result of this work is that the welded joint where the Mar250 was used presented compressive stresses in the weld metal and heat affected zone.