Novel perspectives on machining and surface metallurgical characteristics of X40CrMoV51 in two different heat-treated states with finishing-PMEDM operation
Van Tao Le
Abstract
X40CrMoV51 alloy in heat-treated (HT) and non-heat-treated (NHT) states using electro-discharge machining (EDM) with suspended tungsten compound powder has been scarcely explored. This research investigates the influence of control parameters, such as peak current-Ip, pulse on time-Ton during finishing-EDM, powder amount-TCp, and the material states, on machining characteristics including material erosion rate of the workpiece-MERW and electrode-MERE, and surface metallurgical properties such as re-solidified layer thickness-RSLT, micro-crack acreage percentage-MCAP, chemical composition and its distribution, alloy phase development, and surface morphology. The findings revealed differences in machining and surface metallurgical characteristics between HT and NHT material states. Specifically, MERW increases from 0.0267g/min (NHT) to 0.0279g/min (HT), while MERE decreases from 0.00109g/min (NHT) to 0.000981g/min (HT). Additionally, RSLT reduces from 15.598µm (NHT) to 15.105µm (HT), while MCAP declines from 2.053% (HT) to 1.873% (NHT). Variations were also observed in the chemical composition, W2C phase, and surface topography of the two states.