Avaliação da influência do aporte térmico na microestrutura da ZAC de juntas soldadas do aço inoxidável ENDUR 300.

Abstract

Faced with an increasingly competitive and demanding market, steel producers of stainless steel have been developing increasingly resistant and cost-effective products for recommended applications. These steels enjoy a favorable scenario for applications in the most varied fields of engineering. However, there is a lack of information regarding the impacts of the welding process parameters on the final quality of the weld bead. Thus, the objective of this work is to evaluate the influence of the welding heat input on the microstructure of the heat-affected zone (HAZ) of Endur 300 commercial stainless steels. is necessary in order to guarantee that both the phase balance and the mechanical properties of the material are not severely impaired in a subsequent application. The work comprises the characterization of the HAZ of welded joints using the GMAW (Gas Metal Arc Welding) process with thermal inputs of 4.2, 6.7 and 9.1 kJ/cm. Welding was carried out in the three chosen thermal inputs, and then proceeded to the analysis of the base metal and weld beads through Vickers Microhardness tests, traction, 180° guided bending, macroscopy, optical microscopy (OM), fracture analysis (SEM) ending with phase quantification via software. The results showed that the natural cooling rate of the three conditions tested was not enough to cause significant microstructural changes in the balance of the Ferrite and Martensite phases found in the HAZ. Regarding the mechanical properties, the change in heat input also did not impact the final quality of the welded joints.