Application of Multicomponent Wear-Resistant Nanostructures Formed by Electrospark Allowing for Protecting Surfaces of Compression Joints Parts

Abstract

The paper discusses the specific features of the process for forming multicomponent wear-resistant nanostructures on the structural steel of 38X2MЮA grade using the method of electrospark alloying (ESA) in the course of simultaneously saturating the surface layers with carbon (carbonizing), sulfur (sulfidizing) and aluminum (aluminizing), which can be used to improve microhardness and wear resistance, prevent frictional seizure, increase resistance to atmospheric corrosion and, thus, protect the surfaces of the parts for compression joints against fretting corrosion. At processing steel using the ESA method by graphite electrode with the discharge energy of Wp = 0.13; 0.52 and 4.9 J and the productivity of 0.5–2.5 cm2/min, a consistent matter containing sulfur and an aluminum powder is applied to the surface of the part to be strengthened, and then, without waiting for the matter to dry, the alloying process is carried out, while the consistent matter with the content of the aluminum powder of not more than 56% is applied. There were conducted metallographic and durametric analyses of the surface layers of the structural steel after simultaneously aluminizing, sulfidizing, and carbonizing by the ESA method. It was shown that the layer structure consisted of three zones, namely, the white layer, the diffuse zone, and the base metal. While increasing the discharge energy, such surface layer qualitative parameters as thickness, microhardness, and continuity of the white layer as well as surface roughness thereof had been increasing. With increasing the discharge energy, the presence of the enhanced sulfur content in the coating had been increasing from 40 to 100 µm.