Unconstrained optimization for maximizing ultimate tensile strength of pulsed current micro plasma arc welded inconel 625 sheets

Abstract

Nickel alloys had gathered wide acceptance in the fabrication of components which require high temperature resistance and corrosion resistance. The paper focuses on developing mathematical model to predict ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 nickel alloy. Four factors, five level, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical model has been developed by response surface method and its adequacy is checked by ANOVA technique. By using the developed mathematical model, ultimate tensile strength of the weld joints can be predicted with 99% confidence level. Contour plots are drawn to study the interaction effect of welding parameters on ultimate tensile strength of Inconel 625 weld joints. The developed mathematical model has been optimized using Hooke and Jeeves Method to maximize the ultimate tensile strength. © 2012 Springer-Verlag GmbH Berlin Heidelberg.