Investigation of wear resistance of hydraulic pump gear trunnions restored by supersonic flame spraying

The possibility of using the supersonic flame spraying method to restore worn gear trunnions of hydraulic gear pumps of the NSh-U type is substantiated. During comparative bench wear tests, it was found that the wear rate of gear trunnions with coatings formed by supersonic flame spraying of powder materials of the WC-Co-Cr system was 2-3 times lower than that of serial parts without coatings, accepted as the reference standard. The high wear resistance of these coatings is due to the presence of WC tungsten carbide in their structure. The use of high-hardness coatings on gear trunnions leads to an increase in the wear rate of the mating parts (aluminum bushings). To restore worn gear trunnions of hydraulic gear pumps, a powder material of the Plakart-01.20-N brand is recommended, the use of which makes it possible to increase the relative wear resistance of the gear trunnion by 1.2 times and ensure the durability of the restored «gear trunnion-bearing sleeve» pump joint at the serial level.