Influência da energia de soldagem na microestrutura e na microdureza de revestimentos de aço inoxidável duplex

Abstract

Duplex stainless steels (DSS) are characterized by the presentation of an interesting combination of good mechanical properties and corrosion resistance, having a wide application in chemical and petrochemical industry. Generally, the manufacture and repair of any industrial equipment involve welding operations, even though it is very important to evaluate the influence of welding parameters. It is very important to obtain appropriate ferrite content in the weld metal, so that the variation of heat input can influence on the ferrite content directly. Therefore, the aim this work is to evaluate the influence of the heat input on the microstructure and the microhardness of the weld metal of the DSS. The weld overlay were performed with deposition of two layers on the structural steel ASTM A516 Gr.60, using as filler metal the AWS E2209-17 coated electrode. Three energy levels (15, 20 and 24 kJ/ cm) were used, varying the welding current and speed. It was verified that for energy levels used didn't have significant difference on the ferrite content, but the first bead deposited had a higher austenite content in relation to other beads. All conditions got microhardness below the critical value.