LAUSR

ABSTRACT Three various 12CrNi2 alloy steels were successfully fabricated on 35CrMo alloy steel by laser melting deposition with the aim of investigating the effect of powder oxygen content on formability of 12CrNi2 alloy steel. The phase constituents, macroscopic morphology, microstructure, and microhardness of powders and samples were studied by some modern analysis methods. The experimental results showed that with the increase of the oxygen content from 220 to 600 ppm, the sphericity and density of the powders gradually decreased which led to the appearance of pores in the as-deposited samples. The phase constituent of three as-deposited samples with different oxygen contents was α-Fe(M) phase. The percentage porosity in the macroscopic morphology increased with the increase of the oxygen content. Meanwhile, the high oxygen content contributed to more pores and the crack formation in the microstructure. With the increase of oxygen content, the microhardness of the as-deposited samples would decrease.