New insights into the surface features of SKD61 steel at heat-treated and non-heat-treated states as processed by powder-mixed EDM

•SKD61 steel surface in non-heat-treat and heat-treat states after PMEDM was explored.•Micro-cracks in heat-treated states are higher than those in no-heat-treated states.•Composition of elements, and distribution of C and W in two states are dissimilar.•The intensity of W2C at no-heat-treat states is larger than that at heat-treat states.•The surface topography of no-heat-treated sample has more uniformity. In this paper, the two states of SKD61 steel include heat-treated (HT) and non-heat-treated (NHT), were processed by powder-mixed electrical discharge machining (PMEDM) using tungsten compound powder. Several machined surface properties were investigated by methods such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), 3D Laser Scanning Microscope, and X-ray diffraction (XRD). In both states, their surfaces were changed in chemical composition and content of elements (CCCE), and tungsten carbide phase (W2C) was created. In comparison with the HT state, some surface features of NHT specimens, such as: the percentage of micro-crack acreage per surface (PCAS) is better improved, the penetration of the W element into surfaces and the intensity of the tungsten carbide phase are larger, the distribution of C and W elements on the surface is a more even, and the surface topography has more uniformity and flatness.