Research on wear resistance of carbonized 45 steel by electro-spark deposition technology

Abstract

Electro-spark deposition (ESD) is a green manufacturing method which is more energy-efficient than traditional heat treatment methods and has minimal environmental pollution. ESD enables rapid carburization of metal surfaces by the graphite electrode. Thus, the wear resistance property of the metal surface is improved. ESD can carburize the surface of large steel structure parts in agriculture, improving wear resistance and service life. The traditional carburizing process costs much money and is difficult to achieve. ESD carburizing can save much money and even carburize the partial surface of the part. The traditional carburizing process cannot achieve these. This research employed rapid ESD equipment with rotary electrodes for the surface carburization of No.45 steel. The experiments used the Taguchi orthogonal array (OA) factorial design method. The four critical factors of the ESD process, such as energy, duty cycle, voltage and frequency, were tested. Four parameters and four levels were used to perform sixteen groups of carburizing experiments. The freestate graphite powder was removed from the surface of the deposited samples. The deposited surfaces were analyzed by X-ray diffraction (XRD). According to the diffraction pattern, the composition of the material was compared. It was found that wear-resistant Fe3 C and modified sintered graphite. The linear reciprocating dry friction experiments at room temperature were carried out with a 6mm CrO2 friction ball under 15N pressure. The ultra-deep field microscope was used to examine the experimental surfaces, and the characterization parameters were based on the abrasion marks. The parameters were characterized by an ultra-deep field microscope and analyzed according to the abrasion marks. The abrasion marks can help to obtain three feasible deposition process solutions. Finally, the extreme value design of Taguchi OA was carried out on the width of abrasion marks. The optimized process solution was obtained and verified by experiments. In this article, abrasion mark method can better characterize the wear resistance of materials than other methods. The abrasion marks method was more convenient when the interface between the coating and the substrate (such as carburized materials)was not obvious. The process scheme can help enterprises solve the carburizing process of large carbon steel parts.