Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNS S32760) welds using the Taguchi method

In the present work, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the pulsed current gas tungsten arc welding (PCGTAW) parameters for the corrosion resistance of super duplex stainless steel (UNS S32760) welds. A L9 (34) orthogonal array (OA) of Taguchi design which involves nine experiments for four parameters (pulse current, background current, % on time, pulse frequency) with three levels was used. Corrosion resistance in 3.5%NaCl solution was evaluated by anodic polarization tests at room temperature. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. The higher the better response category was selected to obtain optimum conditions. The optimum conditions providing the highest pitting potential were estimated. The optimum conditions were found as the second level of pulse current (120 A), second level of background current (60 A), third level of % on time (80) and third level of pulse frequency (5 Hz). Under these conditions, pitting potential was predicted as 1.04 VSCE that was very close to the observed value of 1.06 VSCE. As a result of Taguchi analysis in this study, the pulse current was the most influencing parameter on the corrosion resistance and the background current had the next most significant effect. The percentage contributions of pulse current, background current, % on time, and pulse frequency to the corrosion resistance are 66.28%, 25.97%, 2.71% and 5.04%, respectively. Consequently, the Taguchi method was found to be promising technique to obtain the optimum conditions for such studies. Moreover, the experimental results obtained confirm the adequacy and effectiveness of this approach.

[1]  W. Tsai,et al.  Microstructure and pitting corrosion in simulated heat-affected zones of duplex stainless steels , 2002 .

[2]  I. Vergili,et al.  Optimization of filtration conditions for CIP wastewater treatment by nanofiltration process using Taguchi approach , 2010 .

[3]  J. Lippold,et al.  The relationship between chromium nitride and secondary austenite precipitation in duplex stainless steels , 2003 .

[4]  Selim Altun,et al.  Taguchi approach for optimization of the bleeding on cement-based grouts , 2005 .

[5]  S. Harada,et al.  Quality and productivity improvement in aluminium alloy thin sheet welding using alternating current pulsed metal inert gas welding system , 2001 .

[6]  R. Roy.  A Primer on the Taguchi Method , 1990 .

[7]  B. Bacroix,et al.  Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds , 2008 .

[8]  T. Senthil Kumar,et al.  Influences of pulsed current tungsten inert gas welding parameters on the tensile properties of AA 6061 aluminium alloy , 2007 .

[9]  M. Lohrengel,et al.  Micro-electrochemical polarization study on 25% Cr duplex stainless steel , 2004 .

[10]  J. Nilsson.  Super duplex stainless steels , 1992 .

[11]  N. Murugan,et al.  Optimization of pulsed GTA welding process parameters for the welding of AISI 304L stainless steel sheets , 2009 .

[12]  V. Linton,et al.  Failure of a super duplex stainless steel reaction vessel , 2004 .

[13]  Madhan Shridhar Phadke,et al.  Quality Engineering Using Robust Design , 1989 .

[14]  J. Pardal,et al.  Characterization of microstructure, chemical composition, corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750 , 2007 .

[15]  S. Wolynec,et al.  Evaluation of the low corrosion resistant phase formed during the sigma phase precipitation in duplex stainless steels , 1999 .

[16]  H. Kim,et al.  Optimization of experimental conditions based on the Taguchi robust design for the formation of nano-sized silver particles by chemical reduction method , 2004 .

[17]  S. Seshadri,et al.  Effect of weld metal chemistry and heat input on the structure and properties of duplex stainless steel welds , 2003 .

[18]  R. Gunn.  Duplex stainless steels : microstructure, properties and applications , 1997 .

[19]  John C. Lippold,et al.  Welding Metallurgy and Weldability of Stainless Steels , 2005 .

[20]  M. Pohl,et al.  Effect of intermetallic precipitations on the properties of duplex stainless steel , 2007 .

[21]  A. Kumar,et al.  Optimization of pulsed TIG welding process parameters on mechanical properties of AA 5456 Aluminum alloy weldments , 2009 .

[22]  J. Pardal,et al.  Influence of microstructure on the corrosion resistance of the duplex stainless steel UNS S31803 , 2008 .

[23]  Kwangmin Lee,et al.  Effect of isothermal treatment of SAF 2205 duplex stainless steel on migration of δ/γ interface boundary and growth of austenite , 1999 .

[24]  D. Northwood,et al.  Optimization of the electrolytic plasma oxidation processes for corrosion protection of magnesium alloy AM50 using the Taguchi method , 2007 .

[25]  R. Newman,et al.  Detection of deleterious phases in duplex stainless steel by weak galvanostatic polarization in alkaline solution , 2006 .

[26]  H. Abreu,et al.  Influence of the grain size on deleterious phase precipitation in superduplex stainless steel UNS S32750 , 2009 .