Technological processes of obtaining functional coatings by electric contact welding. Part 2.

Electric contact welding (ECW) is a promising resource-saving technology for obtaining functional coatings from the waste of tool-making and machine-building production. A clear methodology is a pre-requisite for selecting the materials, equipment, and tools used; stating the order and describing the operations (transitions) performed; and choosing technological modes (parameters). To develop a technique for obtaining, strengthening, and restoring machine parts, the authors studied functional coatings obtained by electric contact welding at the 011-1- 10 “Remdetal” installation. The duration of the welding pulse and pauses was set using the RVI-501 controller. The welding current strength was calibrated through a strip made of 5 mm thick copper grade with the welding current meter IST-02. Based on the analysis of the ECW zone resistance, he authors found that, for the steel belt U12, the optimal value of the compression force of the welding electrodes on the plowshare made of 65G steel will be 1.7 kN. To ensure the highest efficiency of the ECW process and complete overlap of welding sites, and taking into account the mutual movement of electrodes and parts, the authors present the relationships that help pre-set the main parameters of electrical contact welding for all circuits and equipment options: the strength of welding current, its flow time and the pause between pulses, the compression force of welding electrodes, welding speed, overlap coefficients of welding points flow rate of the cooling liquid and their influence on the process flow and the quality of coatings obtained. The presented algorithm can be used in machine-building production and, in particular, repair production for designing technological processes of obtaining functional coatings during the hardening and restoration of machine parts.

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