Investigation of weldment area and ultimate tensile strength of weld during GTAW of Inconel 825

Abstract

In this work investigate weld characteristics of gas tungsten arc welding (GTAW) of popular nickel based alloy (Inconel 825) used is aerospace industry. A Box-Behnken design (BBD) of 27 experimental runs was performed with welding current (I), welding speed (V), gas flow rate (GFR) and arc length (N) considered as weld parameters to investigate two welding characteristics such as weldment area (WA) and ultimate tensile strength (UTS) of the weld. The modeling of the weld characteristics is carried out using regression analysis. The developed models are validated for its adequacy and are found adequate enough for possible implementation. Desirability approach is further carried out to obtain optimum weld parameters by simultaneously maximizing the ultimate tensile strength (UTS) while minimizing the weldment area (WA). The optimum combination of weld parameters isI=100A, V=208.78mm/min, GFR=9.93l/min, and N=2.49mm, which results in WA=7.0980mm2 and UTS=588.86MPa. Model graphs are plotted and ANOVA analysis is carried out for identifying the significant process factors and its influence on the responses. Micro Hardness investigation is further carried out and highest hardness values are observed in the heataffected zone (HAZ) followed by base metal and weld zone.In this work investigate weld characteristics of gas tungsten arc welding (GTAW) of popular nickel based alloy (Inconel 825) used is aerospace industry. A Box-Behnken design (BBD) of 27 experimental runs was performed with welding current (I), welding speed (V), gas flow rate (GFR) and arc length (N) considered as weld parameters to investigate two welding characteristics such as weldment area (WA) and ultimate tensile strength (UTS) of the weld. The modeling of the weld characteristics is carried out using regression analysis. The developed models are validated for its adequacy and are found adequate enough for possible implementation. Desirability approach is further carried out to obtain optimum weld parameters by simultaneously maximizing the ultimate tensile strength (UTS) while minimizing the weldment area (WA). The optimum combination of weld parameters isI=100A, V=208.78mm/min, GFR=9.93l/min, and N=2.49mm, which results in WA=7.0980mm2 and UTS=588.86MPa. Model graphs are plotted and ANOVA analysis...