A Study of Surface Hardness Affecting in Electrical Discharge Machining on AISI P20 Plastic Mould Steel

Abstract

This article aims to show the effects of the EDM process that influences the surface hardness by comparing the hardness values before and after the spark on the plastic mould steel AISI P20. Divided by the heat treatment, there were three different hardness levels: 1) the plastic mould steel AISI P20 through the process of quenching with the hardness value in the range of 690-710 HV; 2) the steel through the process of quenching and then annealing with the hardness value in the range of 470-490 HV; and 3) the non-heat treatment steel (raw material) with the hardness value in the range of 300-320 HV. The condition of EDM spark on the surface workpiece was 3 mm of depth and 10 mm of diameter copper electrode. The experiment was carried out under the cover of hydrocarbon, using dielectric cooling, and removing debris by the side flushing through the 6 mm of diameter pipe with the flow rate of 15 liters per minute. The experiment parameters included on-time duty factor variable, off-time duty factor variable, and current. Based on the experiment, it was found that when the duty factor increased, the hardened workpiece showed the less surface hardness value. At the same time, the annealed, and the non-heat treatment workpieces showed that the hardness values were proportional to the duty factor and the current of the EDM process.

Effect of Heat‐Treatment and NiB–TiO2 Composite Coating on the Tribological Performance of AISI P20 Steel

“…These processes typically involve heating the surface of AISI P20 steel or depositing a thin film onto the mold surface. Laser processing methods, [2,[20][21][22][23][24][25] plasma/ gas nitriding, [22][23][24][25][26] electrical discharge machining, [27][28][29] laminar plasma jet, [14] boronizing, [30][31][32] carburization, [31,33] and physical vapor deposition (PVD) coating, [5,6,9,34] are the most common techniques used to minimize, as much as possible, the failure at mold surface made of prehardened AISI P20 steel.…”