Effect of abrasive water pressure on the surface layer characteristics of duplex stainless steel 2205

Abstract

Abstract The martensitic stainless steel shot with a high number of cycles was applied to the abrasive water jet (AWJ) to study the effect of jet pressures on the surface layer characteristics of 2205 duplex stainless steel. The Almen strips (type A) quantitatively evaluate the AWJ intensity at jet pressures of 50 MPa, 60 MPa, and 70 MPa. The surface layer characteristics were comprehensively studied using scanning electron microscopy, laser scanning confocal microscopy, x-ray diffraction, electron backscatter diffraction techniques, and microhardness tester. It was found that with the increase of the jet pressure from 50 MPa to 60 MPa and 70 MPa, the AWJ intensity increased by 5.0% and 22% and the surface roughness for Ra increased by 16% and 37%. Residual compressive stresses existed in both phases to a depth of more than 200 μm. The austenite hardening rate is higher than that of ferrite, and the maximum residual compressive stress in austenite of the surface layer of the AWJ specimen occurred at the subsurface. The maximum residual compressive stress in ferrite occurred at the surface (50 MPa, 60 MPa) and subsurface (70 MPa). The hetero-deformation induced stresses formed during the plastic deformation of the heterostructured material made the austenitic residual compressive stresses in the surface layer slightly higher than those in ferrite. The surface grain refinement depth exceeded 150 μm, and the degree of austenite grain refinement was higher than that of ferrite. The fraction of deformation-induced martensite and the depth of phase transformation increased with the increase of jet pressure. These changes caused the surface hardening of the specimen, and the jet pressure had a significant effect on the depth of the hardened layer and the microhardness at depth greater than 50 μm.