Predicting the tensile strength and deducing the role of processing conditions of hot wire gas tungsten arc welded pure nickel tubes using an empirical relationship

There is a renewed interest to utilize the advantages of hot wire gas tungsten arc welding (HWGTAW) process in industrial area. This manuscript reports HWGTAW of pure nickel tubes of 4 mm thickness. Design of experiment (DoE) approach was adopted to bring down the number of the joints. Welding plan was executed according to 3 factors, 5 levels central composite design (CCD). Electrode current, wire feed rate and hot wire current were considered as process parameters and varied in 5 levels. DoE approach allowed to develop an empirical relationship which was used to predict the role of process parameters on the tensile strength of joints within the chosen range. The predicted trends were correlated to the observed macrostructure and microstructure. The joint strength varied due to changes in fusion zone grain size and macroscopic level defects such as lack of penetration, incomplete fusion and lack of coalescence.