Microstructural Evolution and Properties of Novel Ferritic Stainless Steel - Mox Prepared by Laser Melting Deposition

Abstract

An investigation was designed to research the effect of molybdenum (Mo) content on the microstructure and properties of novel ferritic stainless steel (FSS) fabricated by laser melting deposition (LMD). In this study, the stainless steel specimens with different Mo content were manufactured using LMD and the microstructures, the microhardness, wear resistance and corrosion resistance of the as-deposited specimens were evaluated. Expermental results demonstrated that the phase composition of the specimens had no change and consisted of α-Fe and carbide M7C3 phase. The typical dendrite and interdendrite structures were observed, and the grains are obviously refined with the increase of Mo element. The microhardness value of as-deposited specimens increased from 643 HV to 803 HV, and the specific wear rate was reduced from 1.14×10-5 mm3/Nm to 5.90×10-6 mm3/Nm, correspondingly one order of magnitude reduction, which verified that the wear resistance was obviously improved. The corrosion current density of FSS-Mo is two orders of magnitude lower than that of FSS, and it shows better impedance parameters, indicating that the addition of Mo can effectively improve the electrochemical corrosion performance of materials.

Keywords: Laser Melting Deposition, Ferritic Stainless Steel, Mo, wear, corrosion