Soldagem e análise de comportamento de materiais dissimilares: aço 1,25Cr-0,5Mo e aço inoxidável 304

Abstract

Dissimilar metal welding is constantly used in various industry segments. Specifically in the oil industry, it is common to find welded materials such as low-alloy chromiummolybdenum steels and austenitic steels, because they have good corrosion resistance and behave well at high temperatures under pressure and temperature cycling conditions. Austenitic matrix Cr-Ni alloy addition metals are used in solders. This study consisted of welding a joint made of ASTM A387 low-alloy steel and AISI 304 austenitic stainless steel, using Cr-Ni alloys as filler metals. Welding was performed manually by the coated electrode welding process (SMAW). The specimens were microstructurally characterized using an optical microscope and submitted to the Vickers microhardness test. The analyzes showed austenite phases in a ferritic matrix in both base metals, but they did not present a good linearity of material properties, first observed by the other phases, grain size and proven with the microhardness results, that a significant variation in hardness was found, mainly in the weld region and thermally affected area, where it showed a large accumulation of stresses and, consequently, a lower resistance to mechanical stresses.