Surface layer characterization of 2205 duplex stainless steel subjected to abrasive water jet descaling

Abstract

Abrasive water jet (AWJ) is an environmentally friendly and acid-free descaling technology, that has the added benefit of strengthening the material surface. However, the effects of AWJ descaling on the surface layer of heterostructured (HS) materials and the application of deformable abrasives involving high cycle times for AWJ descaling have not been extensively reported. In this study, martensitic stainless steel particles with high cycle times were subjected to AWJ descaling to investigate the effect of AWJ on the surface layer characterization of 2205 duplex stainless steel (DSS). The properties of the 2205 DSS surface layer were characterized by the surface morphology, surface roughness, microstructure, and microhardness. When exposed to an AWJ intensity of 0.245 mmA, the surface of 2205 DSS exhibited the formation of extrusion craters and flat debris. Additionally, the surface roughness Ra was measured at 3.778 µm. The gradient hardening layer was formed on the surface of the AWJ specimen, and the depth of the hardening layer was 550 µm. The maximum microhardness was 395 HV, which is approximately 30% higher than that of the original specimen. Within the AWJ specimens, dislocation networks were observed in the ferrite, while the austenite exhibited dislocation cells, deformation twins, and strain-induced martensite. Furthermore, the experimental results indicate that plastic deformation was unevenly distributed between the two phases, with the majority of deformation occurring within the austenite phase. Owing to the requirement of deformation compatibility, several of geometrically necessary dislocations (GNDs) accumulated near the austenitic phase boundary to regulate the plastic strain gradient, and the hetero-deformation induced (HDI) stress generated by these dislocations strengthens the austenite. The AWJ refines the surface material structure; increases the density of dislocations, phase boundaries, and stacking faults; forms strain-induced martensite; and introduces a residual compressive stress field, which improves the material surface hardness.