Modeling And Optimization of Ambient Temperature Of Tig Welding Of Mild Steel Using The Response Surface Methodology

Ambient temperature is the air temperature of any object or environment where equipment is stored. The adjective ambient means "relating to the immediate surroundings and every metal has a particular ambient temperature depending on the metal alloy involved. The design of experiment based on the central composite design method having a total of 20 runs was developed. 20 pieces of mild steel coupons (20 specimen) measuring 60mm x 40mm x 10mm thick were fabricated. The samples were cut longitudinally to have a single-v joint preparation with the edges beveled and machined appropriately. The tungsten inert gas (TIG) welding technique was used for the joining process, while employing 100% pure Argon as shielding gas to protect the weld pool from atmospheric interaction. Experimental results were obtained via a series of measurements and laboratory test. To analyze the input and output data, Response Surface Methodology (RSM) was employed. From the analysis of results, the second order of polynomial model was adopted. To test for the model significance, adequacy and validity, the analysis of variance (ANOVA) was done and goodness of fit was determined. The results showed that the adopted model had a p-value of 0.0001 indicating a model that is highly significant. Based on the RSM numerical optimization, it was observed that a current of 180amps, voltage of 19volts, and gas flow rate of 13L/min will produce ambient temperature of 44.626oC, at a desirability function value of 91.5%. The follow-up experiment demonstrated significant agreement and confirmed the validity of the optimized results