Statistical Evaluation of the Impact Strength on Mild Steel Cladding Weld Metal Geometry

Abstract

The research focused on statistical evaluation of the impact strength on mild steel cladding weld metal geometry. The weld specimen of length 60 mm by width 40 mm and thickness of 10 mm was used for the experiment. A butt joint method was prepared and tungsten inert gas welding process was used to perform the twenty (20) experimental runs. A response surface method was applied to model and to analyze statistically the welded metal bead geometry. The statistical result expressed that the model developed is significance. However, there is only 4.29% chance that an F-Value could occur due to noise. Probability values that is less than 0.0500 indicate that the model terms are significant. In this research, there is 86.09% chance that a Lack of Fit of F-value which is this large could occur due to noise. Non-significant lack of fit is good for the model fitness. It was observed that the R-Squared value of the model is 0.8971 while the Adjusted R-Squared value of the model is 0.7827. Adequate Precision measures the signal to noise ratio and a ratio greater than 4 is desirable. However, the computed  ratio of 8.724 was observed which indicates an adequate signal.  The results of response surface plots and contour plots observe that the process parameters influence the impact strength of the weld bead geometry except voltage, which has no effect on the output parameter. The statistical investigation reveals the statistical solutions necessary to portray the parameters under study.