Efeito dos parâmetros de soldagem do processo PTA nas características geométricas e no teor de ferrita do metal de solda na deposição de aço inoxidável superduplex

Abstract

The aim this work is to evaluate the influence the geometric characteristics and ferrite content in the weld metal in weld overlay on C-Mn steel pipes with SDSS UNS S32760 deposition by PTA process. Taguchi method had been used for experimental arrangement and evaluation of process variables: plasma gas flow rate (1 l/min, 3 l/min and 5 l/min), shielding gas flow rate (10 l/min, 15 l/min and 20 l/min), kind of shielding gas (Ar, Ar + 2,5%N2 and Ar + 25%He) and torch work distance (8 mm, 12 mm and 16 mm). Welding has been performed with only one bead deposited. Later, it had carried geometry analysis and quantification of ferrite content in the weld metal. In relation to the reinforcement, width, wetting, dilution and content ferrite, the SDSS powder was successfully deposited using the PTA welding process: torch work distance – 16 mm; shielding gas – Ar + 25%He; shielding gas flow rate – 15 l/min and plasma gas flow rate – 3 l/min.