QPQ salt bath composite processing on microstructure and property of certain type aviation piston engine ring

QPQ treatment was carried out on the circulation of a certain type of aero-piston engine. Nitrification treatment of 570 °C and 180 min was performed first, oxidation treatment of 400 °C and 20 min was performed, and secondary oxidation of 370 °C and 20 min was performed after polishing. The surface characteristics of the high cycle treated by QPQ were studied by optical microscope, micro hardness tester and friction and wear tester. The results show that the surface of the rising ring after QPQ treatment forms an oxidation film, a Nitriding layer and a diffusion layer from the outside to the inside. The maximum hardness of the ring surface treated by QPQ is 592 HV, which is nearly twice as high as before untreated, and its wear resistance is nearly five times higher than before untreated.