Effect of Laser Selective Melting on the Microstructure and Properties of Martensitic Stainless Steel After Annealing Treatment.

This work investigated the CrNiMo stainless steel using laser selective melting (SLM) technology and explored the effect of the tempering temperature on the microstructure and properties. After the tempering treatment, the quenched martensite transformed from a metastable to steady state, and residual austenite was formed. The results indicated that the elongation of the transverse specimen showed an upward trend as the tempering temperature increased, while the elongation of the longitudinal specimen first increased and then decreased. The fracture mode was ductile. There was an obvious fiber, radial, and shear lip zone on the fracture surface of transverse specimens. When the tempering temperature was 650 °C, the shear lip area of the fracture surface was the largest. For longitudinal specimens, there was no obvious zoning on the fracture surface.