Examining Stress Modification in Dissimilar and Similar Metal Welds through Ultrasonic Impact Treatment

Vollständiger Abstract

Worum geht es in dieser Arbeit?

Residual stress (RS) from welding poses major challenges, especially in dissimilar joints such as 1018 steel and 304 stainless steel, where thermal expansion mismatches intensify tensile stress. Conventional post-weld heat treatments, although effective for homogeneous materials, often require substantial energy, specialized equipment, and extensive processing time, making them less practical for dissimilar metal weld applications. This study explores an alternative, energy-efficient method — ultrasonic impact treatment (UIT) — to address RS in both similar and dissimilar metal welds. This study employs UIT on the top and bottom surfaces of welds and measures RS in the longitudinal, transverse, and normal directions using neutron diffraction at a high flux isotope reactor. Findings reveal that UIT significantly reduces longitudinal RS in similar welds but introduces moderate increases in transverse and normal RS due to stress redistribution dynamics. UIT demonstrates strong potential for RS modification; however, its application to dissimilar welds, such as 1018 and 304, requires careful parameter control to account for asymmetric material behavior and ensure consistent stress relief.