Tribological performance of gas tungsten arc welded dissimilar joint of sDSS 2507/IN-625 for marine application

Abstract

The present study utilizes a slurry-pot wear tester to investigate the relationship between slurry concentration and slurry-erosion performance of sDSS 2507/IN625 dissimilar weld joint (DWJ). Varying slurry concentrations (10 and 30 wt.% silica sand) were utilized to investigate erosion, weight loss, and wear mechanisms in severe environments. The study aimed to provide an in-depth knowledge of erosion behaviors by analyzing surface characteristics, microstructure characteristics, and material removal mechanisms. The electron probe micro-analyzer studied weld zone element segregation and scanning electron microscopy (SEM) examined microstructure and erosion mechanism. ER2594 filler weld shows higher microhardness as compared to weld fabricated using ERNiCrMo-3 filler metal. Sand particle density, particle-to-surface contact, particle interactions, and fluid impacts increase cumulative weight loss and decrease erosion rate per unit solids weight. Slurry concentration increased weight loss by 23% for sDSS 2507 BM and 33% for IN-625 BM. ER2594-LHI lost 72% and ERNiCrMo-3-LHI 77% more weight with increasing slurry concentration. Filler ERNiCrMo-3 has less erosion wear than filler ER2594 as the concentration of slurry increases. SDSS 2507 BM and IN-625 BM erode 1.45 and 1.8 times faster with increasing slurry concentration, respectively. The erosion rate of ER2594-LHI and ERNiCrMo-3-LHI increases 0.85 and 1.2 times with slurry concentration. SEM analysis of the worn surface exhibits mixed cutting–ploughing modes coexisting with the formation of craters. The material removal has predominantly occurred from the cutting and ploughing mechanism, whereas the characteristic presence of craters and frontal and lateral lips is also found across the entire surface. The results from this study suggest the optimum heat input to be maintained during weld fabrication of sDSS 2507/IN-625 using ER 2594 and ERNiCrMo-3 filler metals for enhanced resistance against slurry erosion wear. Also, an insight into the wear mechanism helps in understanding the effect of microstructural features on the wear performance of welds in operational conditions.