Understanding the parameters controlling plasma transferred arc hardfacing using response surface methodology

Control of dilution is important in hardfacing, where typically low dilution is desirable. At present, majority of the fabrication industries use shielded metal arc welding (SMAW), gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and submerged arc welding (SAW) processes for hardfacing purposes. In these processes, the percentage of dilution level is higher, ranging between 10-30%. In plasma transferred arc (PTA) hardfacing, a solidified metallurgical bond between deposit and substrate is obtained with minimum dilution (less than 10%). This article highlights the application of response surface methodology (RSM) to predict and optimize the percentage of dilution of nickel based hardfaced surface produced by PTA process. The experiments were conducted based on five-factor, five levels central composite rotatable design with full replications technique and mathematical model was developed using RSM. Further, the RSM is used to optimize the process parameters that yield the lowest percentage of dilution.