Wang Yongkang, Tang Jie, Chen Jianzhi, Nie Zhibin, Zhao De
School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China.
Henan Diesel Engine Heavy Industry Co., Ltd., Luoyang 471039, China.
Materials (Basel). 2024 Jul 24;17(15):3643. doi: 10.3390/ma17153643.
Existing optimization research on the crankshaft heat treatment process is mostly based on one-sided considerations, and less consideration is given to the matching of multiple process parameters, leading to irrational designs of heat treatment. To address this problem, this work investigates the influence mechanisms of cooling speed, tempering temperature, and holding time on the performance evaluation indexes of the straightness, residual stress, and martensite content of a crankshaft based on the response surface method. The results showed that the order of influence of these three different process parameters on the performance evaluation index was cooling speed > holding time > tempering temperature, and the order of influence on the performance evaluation indexes under multifactorial process parameters was cooling speed-holding time > cooling speed-tempering temperature > holding time-tempering temperature. The optimal process parameters were a cooling speed of 1.4 times the cooling oil, a tempering temperature of 555 °C, and a holding time of 6 h, with the straightness of the crankshaft reduced by 9.9%, the surface stress increased by 6.7%, and the martensitic content increased by 7.2% after the process optimization. This work can provide new clues for optimizing the heat treatment process parameters of crankshafts.
现有的曲轴热处理工艺优化研究大多基于片面考虑，较少考虑多个工艺参数的匹配，导致热处理设计不合理。为解决这一问题，本研究基于响应面法研究了冷却速度、回火温度和保温时间对曲轴直线度、残余应力和马氏体含量等性能评价指标的影响机制。结果表明，这三个不同工艺参数对性能评价指标的影响顺序为冷却速度＞保温时间＞回火温度，多因素工艺参数下对性能评价指标的影响顺序为冷却速度-保温时间＞冷却速度-回火温度＞保温时间-回火温度。优化后的工艺参数为冷却速度为冷却油的1.4倍、回火温度为555℃、保温时间为6h，工艺优化后曲轴直线度降低了9.9%，表面应力增加了6.7%，马氏体含量增加了7.2%。本研究可为优化曲轴热处理工艺参数提供新的思路。
