Riazantsev A. Improvement of wear resistance of large-modular gears by surface plasma-arc reinforcement

The work is devoted to the increase of wear resistance of large-modular gears due to the application of the innovative method of surface plasma-arc reinforcement (SPAR) working surfaces of teeth. The influence of the physical and mechanical properties of the gear wheels' material on the intensity of wear in the period of tire work and the established uniform wear of the contact surfaces of the teeth has been determined, as well as the substantiated possibilities of their productive surface plasma-arc reinforcement. The method of determination and estimation of the residual resource of large-modular gear transmissions after SPAR is developed and the influence of technological parameters of this process on wear resistance and mechanisms of deterioration of the surface layer have been investigated. The optimization of the parameters of the process of increasing the wear resistance of gears by means of mathematical modeling of the SPAR processes of gear wheels was carried out and the optimal ratios of the velocity of the heat source movement and the current strength of the plasma arc (Vopt = 350 mm/min, Iopt = 245 A) were obtained, which allowed establishing an increase in service life gear wheels. The process of SPAR has been experimentally investigated, the method of thermophysical research has been developed and implemented, an estimation of the obtained physical and mechanical properties and hardness of the processed material during plasma heating has been made. The increase of durability of the work of large-modular gears passing by the SPAR has been experimentally investigated and the calculations on durability have been performed for the wear parameter, and it has been established that the application of this heat treatment method increases the durability 2.28 times. A complex of specialized equipment was developed for the implementation of the technological scheme of plasma-arc surface reinforcement of the large-modular gears' working surfaces without melting, using the original design of the magnetic-deflection system for the creation of an external magnetic field.