Optimization of Cladding Index in GMA and Universal-GMA Stainless Steel Cladding Using Response Surface Methodology

摘要

In weld cladding the opposing nature of deposition rate and dilution, owing to the inherent nature of the welding arc, affects the quality and economy of a cladding operation directly, which makes it difficult to arrive at a correct parametric combination for cladding. So keeping in view the importance of a variable which would involve both i.e. deposition rate and dilution, a new variable named as 'cladding index' (ratio of deposition rate to dilution) was introduced in the present work. This variable was optimized through the present experimental work, besides investigating the efficacy of a new variant of GMAW process named as UGMAW (Universal gas metal arc welding) process in controlling cladding index in stainless steel cladding. Four factor five level central composite rotatable design was used to develop relationship for predicting cladding index, which could enable quantifying of the direct and interactive effects of four numeric factors viz. wire feed rate, arc voltage, welding speed and contact-tip-to work distance and one categorical factor preheat current. Since cladding index (CI) was a dependent response variable, the overall trend followed by 'CI', as the process variables were changed through their operating ranges, was the outcome of the interplay between various direct and interaction effects that affected deposition rate and dilution, independently. Furthermore, optimization capabilities in the Design-expert software were used to optimize the input process parameters using different criteria for obtaining optimum numerical solutions as per the cladding conditions desired. This study not only aided in achieving optimum cladding conditions but also helped in exploring and establishing the productivity enhanced features of UGMAW process for cladding applications.