Properties of Water Atomized 25Cr7Ni Stainless Steel Processed by Laser-Powder Bed Fusion

Abstract

The 25Cr7Ni stainless steel is characterized by its two-phase microstructure consisting of ferrite and austenite, contributing to an excellent combination of mechanical and corrosion properties. The present study examined the effects of laser energy density and laser powder bed fusion (L-PBF) process parameters on the physical, mechanical and corrosion properties of a water atomized 25Cr7Ni stainless steel powder processed through L-PBF. The results from the study saw that a combination of L-PBF process parameters (laser scan speed and laser scan spacing at a constant layer thickness) as critical factors affecting the mechanical and corrosion properties of the printed samples. The Archimedes density, mechanical and corrosion properties of samples improved with increase in energy density. The as-printed samples displayed single-phase ferritic microstructure and higher mechanical strength (1050 MPa) compared to wrought, metal injection molded (MIM), powder metallurgically sintered (PM) 25Cr7Ni stainless steel (super duplex stainless steel) alloys. The samples exhibited comparable corrosion resistance to that of a wrought 25Cr7Ni stainless steel despite the presence of only ferritic microstructure.