Electronic microscopy of the surface of SCMnCr3 steel after electric spark treatment with a tungsten electrode-anode

Abstract

The method of scanning electron microscopy was used to study the surface morphology of steel SCMnCr3 after its electrospark treatment with a tungsten (without additives) anode electrode. The following structural elements have been identified: bulges, spherical and disk-shaped inclusions, cracks, pores and particles of irregular shape. Their appearance is due to high temperatures in the interelectrode gap (higher than the corresponding melting temperatures of the main electrode materials) and the non-equilibrium of the processes occurring in it. During the formation of pores, the main mechanism is the release of gases during cooling of the electrode materials in the liquid phase. Macrostresses arising from an electric spark discharge in the surface layers of the electrodes, which exceed the mechanical properties of the electrode materials, lead to the ejection of irregularly shaped solid particles into the interelectrode gap and the appearance of cracks. The appearance of sagging, round/oval inclusions, and spherical particles is associated with the interaction of the liquid phase from the interelectrode gap with the cathode surface.

Keywords

• steel
• tungsten
• electrospark processing
• morphology
• electron microscopy