Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
AUSTENITIZATION OF WELDING BEADS IN A S32750 MADE WITH ND:YAG PULSED LASER THROUGH HEAT TREATMENT
Submission Author:
Dair Ferreira Salgado Junior , MT
Co-Authors:
Dair Ferreira Salgado Junior
Presenter: Dair Ferreira Salgado Junior
doi://10.26678/ABCM.COBEM2019.COB2019-0238
Abstract
Duplex and super duplex stainless steels, 50% austenite and 50% ferrite, combine the most desirable characteristics of ferritic and austenitic steels, have excellent mechanical and corrosion resistance for a wide variety of media with significant corrosion resistance in water of the sea and other environments containing chloride, due to its high level of chromium, molybdenum and nitrogen. When welded the region of the weld metal of these steels lose their characteristics of mechanical resistance and corrosion due to the imbalance of the ferrite and austenite phases. In the present research the effect of heat treatments after autogenous welding was investigated. Pulsed Nd: YAG to increase the amount of austenite in the weld bead in UNS S32750 super duplex stainless steel plates. A pulsed laser source Nd:YAG, United Winner 150A, was used with a maximum power of 150 W. The welding pulse energy was fixed at 30J, peak power of 2 kW and temporal width of 5 ms in wave form, and descent ramp varying from 20 ms with frequency variation and displacement speed. Pure argon with flow rate of 22 l / min was used as protection gas. The microstructural characterization was performed by optical microscopy applying Behara modified for surface attack. The results showed the obtaining of 30% of austenite.
Keywords
Nd:YAG, Heat treatment, austenite, ferrite phase, LASER
