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本文研究了40C_r钢φ50mm及φ170mm试样中残余应力与回火冷却制度的关系。表明调质大轴中的残余应力主要取决于回火中在高温阶段(工件心部温度高于400℃时)的冷却速度;低温阶段(心部达400℃以后)冷速的影响甚小。瞬时弹性应力计算表明,对φ800mm以下的调质大轴,当其心部温度降至400℃后出炉空冷,其瞬时弹性应力将不超过12kg/mm~2。
This paper studies the relationship between the residual stress and the tempering cooling system in the specimens of φ50mm and φ170mm for 40C_r steel. The results show that the residual stress in quenched and tempered large shaft mainly depends on the cooling rate during tempering at the high temperature (the core temperature of the workpiece is higher than 400 ℃) and the cooling rate at low temperature (after the core reaches 400 ℃). The calculation of instantaneous elastic stress shows that the instantaneous elastic stress will not exceed 12kg / mm ~ 2 for the quenched and tempered large shaft below 800mm when its core temperature drops to 400 ℃ and then air-cooled.