Effect of high-pressure rolling followed by laser processing on mechanical properties, microstructure and residual stress distribution in multi-pass welds of 304L stainless steel

Abstract

Multi-pass fusion welding by a filler material (wire) is normally carried out to join thick steel sections used in most engineering applications. Multiple thermal cycles from a multi-pass weld resulted in a variable distribution of residual stress field across the weld and through the thickness. Presence of tensile residual stresses can be detrimental to the integrity and the service behaviour of the welded joint. In addition to a complex distribution of residual stress state, multipass welds also form dendritic grain structure, which are repeatedly heated, resulting in segregation of alloying elements. In this research, microstructural refinement with modification of residual stress state was attempted by applying post-weld cold rolling followed by laser processing and then cold rolling. The residual stress was determined non-destructively by using neutron diffraction. Post-weld cold rolling followed by laser processing was carried out to induce recrystallization of the cold rolled grains. Microstructural characterisation indicates a significant grain refinement near the capping pass. However, post-weld cold rolling followed by laser processing reinstates the lock-in stress. In this study, it was demonstrated that a complete recrystallized microstructure with compressive state of stress can be formed when a further cold rolling is applied on the laser processed, recrystallized microstructure.

Study of fatigue crack growth characteristics of TIG welded AZ31B magnesium alloy joint based on laser bionic treatment

“…The HAGBs inhibit or even interrupt the linear cracks growth, 30 leading to deflection and branching of cracks. The HAGBs can also increase the toughness of material, 35 which was demonstrated by the dimple aggregation-type toughness fracture of laser bionic specimens (Figures 9H and 10G). The improvement of toughness was beneficial to retarding FCG and improving the fatigue property.…”

Effect of faying surfaces and characterization of aluminium AA6063–steel AISI304L dissimilar joints fabricated by friction welding with hemispherical bowl and threaded faying surfaces

“…The melting point of AISI304L alloy is almost two times greater than AA6063 alloy, so a huge variation is there in the performance while welding. AISI304L is widely used in many applications due to excellent properties [19] and it is also becoming popular for the combination with other material. The properties of weld metals are reported in Table 2.…”

Influence of Laser Beam Wobbling Parameters on Microstructure and Properties of 316L Stainless Steel Multi Passed Repaired Parts

“…With each subsequent pass, the welding deformations increase. Reducing the number of passes by using special grooves can reduce the negative effect of overheating on welding deformations [10,20,32,33].…”