Optimization and Prediction of Ultimate Tensile of TIG Mild Steel Welds Using RSM

Abstract

TIG welding, is about the most popular welding method, which finds its applications in the fabrication industry. The integrity and service life of engineering structures is a very important factor in the welding technology sector, one of the problem facing the fabrication industry is the control of the process input parameters to obtain a good welded joint . Research has shown that one of the practical ways to improving on weld qualities is to optimize the input process parameters. The aim of this study is to optimize and predict the ultimate tensile strength of TIG mild steel welds using RSM with the purpose of achieving the highest tensile strength.In this study, twenty experimental runs were carried out, each experimental run comprising the current, voltage and gas flow rate, the TIG welding process was used to join two pieces of mild steel plates measuring 60 x40 x10 mm , the tensile strength was measured respectively. Thereafter the data collected from the experimental results was analysed with the RSMAnalysis of variance (ANOVA) a p-value  of 0.0001 which is <0.005 indicates that the model is significant To validate the significance and adequacy of the model based on its ability to optimize the uultimate tensile strength and impact energythe goodness of fit statistics showns that the model posses an R² value of 0.905 and R² adjusted of 0.837 a noise to signal ratio of 12.897  was realized, a ratio greater tha 4 is desired  indicating thatt the model possesed adequate signal  to predict the target response.the result shows that a combination of current 90 amps,voltage 22volts and gas flow rate 13lit/min will produce an optimum UTS of 381Mpa  with a desiribility value of 0.889.