Analysis of Design of Experiments Methodology for Optimization of Pulsed Current GTAW Process Parameters for Ultimate Tensile Strength of UNS S32760 Welds

Abstract

This work deals with the improvement of ultimate tensile strength (UTS) of super duplex stainless steel (SDSS, UNS S32760) welds fabricated by pulsed current gas tungsten arc welding (PCGTAW) process. The Taguchi method, a design of experiment technique, was employed to optimize PCGTAW process parameters to improve the UTS of SDSS weldments. The optimum conditions were found to be the second level of pulse current (120 A), second level of background current (60 A), first level of % on time (40) and second level of pulse frequency (3 Hz). Under these conditions, UTS was predicted as 776 MPa that was very close to the observed value of 769 MPa. Analysis of variance (ANOVA) was performed on the measured data and signal-to-noise ratios. As a result of ANOVA, the % on time was found to be the most significant factor affecting the UTS of SDSS welds by percentage contribution of 62. 23. The pulse current (21. 13%) and the background current (16. 18%) had also the next most significant effects on the UTS. The pulse frequency with the 0. 46% contribution was insignificant. © 2012 Springer Science+Business Media, LLC and ASM International.