The effect of repeated welding cycles on the microstructure and ferrite content of 25cr super duplex stainless steel weld metal by automatic orbital tig welding

The objective of this research is to evaluate the macrostructure, microstructure, chemical elements and ferrite content of 25Cr Super Duplex Stainless Steel (SDSS) UNS S32750 weld metal after the condition of repeated welding cycles. TIG automatic orbital is used to weld tubing test specimen size 9.53mm diameter and 2.1 mm thickness at heat input 0.248 kJ/mm, the torch is orbiting surface circumference and melting down in 2G position with shielding gas protection of 99.99 Argon in DC negative polarity, this welding process able to melt down two opposite square-end of base metal without filler metal. All test specimens are evaluated by simulating of three repeated welding cycles consist of original welding, R1, R2, and R3. The results of this research are indicating there are correlation between metallography, chemical analysis and ferrite content to the increasing number of welding cycles. ©2006-2016 Asian Research Publishing Network (ARPN).