Estudo dos parâmetros operacionais e do balanço de fases na soldagem com arame tubular do aço inoxidável UNS S31803

Abstract

It is known that stainless steels have an extremely wide range of applications. When the use of stainless steels with special characteristics, that combine good corrosion resistance and good mechanical strength is necessary, duplex stainless steels (DSS) are ideal, since they have a microstructure composed of austenite and ferrite that, when balanced, provide these good properties. When manufactured, DSS components are usually subjected to welding processes. Among the various types of welding processes, the Flux-Cored Arc Welding allows the welding of these materials at high deposition rates and provides them with great metallurgical versatility. This work aims to study the different configurations of welding parameters for UNS S31803 steel and to analyze the influence of these parameters on the geometry of the weld beads and on the phase balance. Initially, the influence of the current, CTWD, and the torch inclination angle on the variables width, reinforcement, penetration, dilution and surface appearance were evaluated. After this exploratory study, it was decided to study the effect of the following control factors: current, CTWD, welding speed, and position of the sample on the weld bead (initial and final), on the response variables, along with the analysis of the impact of these adjustments on the phase balance. During the preliminary study, it was observed that the current has a significant influence on all the response variables. Besides, during the final welding part, it was observed that the control factors, except for the position, had significant influence on the phase balance. This occurred because the adjustment of these parameters also changed the welding energy, what made the weld beads achieved with greater energy to show a greater amount of austenite in their final composition compared to those obtained with less energy. As for the position of sample on the weld bead (initial and final), it was verified that it did not present a statistically significant influence on the amounts of ferrite and austenite.