(1) fine car increase stress relief annealing, and improves the stress relief annealing temperature. In does not affect the matrix organization as the premise of sorbite as much as possible under high temperature, and prolonging the holding time, the machining stress fully release. Increase the stress relief annealing in nitriding fine car, stress can eliminate the rough machining, finish machining to improve dimensional stability.
(2) the keyway prepared false key, so that the section of axis of symmetry, prevent the distortion caused by asymmetric cross-section of nitriding.
(3) to adjust the nitriding process, is composed of two sections of nitriding to three stage nitriding, nitriding temperature and nitriding can improve, each time, and the original after nitriding furnace cooling to 150 ℃ baked into the furnace, furnace cooling to room temperature, this can increase the nitriding efficiency, reduce the distortion.