We Shenzhen sushi heat treatment of 40Cr steel gear surface punctate stripping failure analysis, draws the conclusion and suggestions to share with you:
(1) the failure of the gear is made of 40Cr steel, the components meet the technical requirements. Gear surface nitriding layer depth and hardness meet the design requirements, but the matrix organization is not quenched annealing microstructure, hardness is low, do not meet the design requirements.
(2) in the experiment of running gear, pits, pits and flaking defects formed tooth surface contact fatigue damage is. The reason is because the gear in the pre nitriding in the furnace has experienced over high temperature for a short time, so after quenching and tempering microstructure and re annealing, leading to gear strength and low hardness, load caused by tooth surface nitriding layer is pitting and spalling.
Suggestions on gear nitriding process, must strictly temperature detection box control of each process stage furnace, seriously implement the rules of operation. At the same time can surface nitriding layer depth increasing.
Shenzhen Su's heat treatment is a professional nitrogen gas, liquid nitrogen, QPQ salt bath processing factory.