Laser metal deposition of vanadium-rich high speed steel: Microstructural and high temperature wear characterization

[摘要] A comparative high temperature wear study was conducted between two alloys: laser metal deposited vanadium-rich (V-rich) high speed steel (HSS) and spun cast carbide enhanced indefinite chilled double poured (CE-ICDP) iron. Laser Metal Deposition (LMD) of V-rich HSS alloy was performed by using a 4.0 kW Nd:YAG laser at three different laser scan speeds to investigate the effect thereof on the carbide size and morphology, phase constitution and mechanical properties (such as micro-hardness and wear resistance) of the laser metal deposits. A comprehensive microstructural characterization of these alloys revealed that the dendritic microstructure of the V-rich HSS alloy consisted of martensitic matrix and VC carbides. Increasing the laser processing speeds significantly changed the morphologies of VC carbides from square and round to angular and rod-like shapes. The micro-hardness of the V-rich HSS was improved from 760 HV to 835 HV by increasing the laser processing speed. During high temperature (500 degrees C) pin-on-disc wear tests, the V-rich HSS showed excellent wear resistance compared to CE-ICDP iron. It was found that V-rich HSS with square and round shape VC carbides (V-rich 10 mm/s) showed the most improved tribological performance with oxidative wear found to be the dominant wear mechanism at this temperature.

[发布日期] 2019-04-25

[效力级别]  Proceedings Paper

[关键词] High speed steel;Laser metal deposition;Microstructural refinement;Hot metal forming;Carbide morphology;Oxidative wear