ПЛАСТИЧЕСКАЯ ТВЕРДОСТЬ КОМПОЗИЦИОННЫХ ПОКРЫТИЙ НА ОСНОВЕ ХРОМА

Abstract

One of the common problems leading to the failure of agricultural machin-ery units is a significant change in their geometric characteristics, which is associated with the wear of individual elements of power hydraulic equipment. To restore these parts, it is advisable to use methods of applying a dispersed-hardened galvanic com-posite coating, accompanied by the introduction of tool material into the coating due to direct contact of the tool with the workpiece. As a result, wear-resistant sediments with specified physical and mechanical properties are obtained, depending on the amount of wear of various sections of the surface being restored. (Research purpose) The research purpose is determining the strength parameters of dispersed-hardened galvanic composite coatings used for the restoration of power hydraulic equipment of agricultural machinery. (Materials and methods) Hydraulic cylinders of the drive of working bodies of agricultural machinery were used as experimental samples. It was noted that the coordinated change in tool pressure depending on the degree of wear of the surface makes it possible to obtain dimensional coatings with specified properties. (Results and discussion) A comparison of the results obtained in solving the contact problem of the contact of two bodies, solved by the methods of continuum mechan-ics, and experimental studies, and determined for this type of composite material the relationship between the magnitude of the force of pressing particles into the coating and the depth of their penetration. The conducted research allowed us to introduce the concept of plastic hardness, which qualitatively and quantitatively characterizes the properties of the resulting galvanic precipitation. (Conclusions) The relations obtained in the work allow us to control the process of forming a composite galvanic deposit during the restoration of power hydraulic equipment of agricultural machinery, preventing overhardening of such a coating, and setting it the required degree of hardening.