Optimal Arc Welding Process Parameter Combination Design and Metallographic Examination for SDSS Butt Welds

Abstract

Although novel techniques and high performance material open the way for generation of high-performance welded joints, the welding operations are inherently quite complex and expensive. This has been the case, especially for super duplex stainless steel (SDSS) welding. If inappropriate parameter combinations are selected, then the welding process degrades the strength and corrosion resistance because of an unbalanced ferrite/austenite content in an SDSS welded joint. Therefore, it is vital to determine the optimal combination of parameters such as welding process, rate of shielding gas, heat input, and weld geometry. In addition, the optimal combination of parameter levels plays an important role in maintaining the microstructural and mechanical properties in the weld's metal region. This paper illustrates an expert knowledge based methodology for designing the optimal parameter combination, using an engineering robust design approach (ERDA) and related experimentation results. The experiments were performed to investigate the effect of welding factors (i.e., gap geometry, different welding techniques, material transfer and welding processes) on the material properties in the weld and heat affected zone (HAZ). The optimal parameter combination, results of the verification experiment, and the metallographic examination results of selected regions of the butt welded joints are presented.