某汽车曲轴热锻模喷丸强化  

Shot peening strengthening on hot forging die for an automobile crankshaft

作　　者：刘绍波[1] 李晓峰 王亚军[2] Liu Shaobo;Li Xiaofeng;Wang Yajun(College of Intelligent Manufacturing and Automobile,Chongqing Technology and Business College,Chongqing 401520,China;College of Material Science and Engineering,Chongqing University,Chongqing 400030,China)

机构地区：[1]重庆工商职业学院智能制造与汽车学院,重庆401520 [2]重庆大学材料科学与工程学院,重庆400030

出　　处：《锻压技术》2023年第6期185-190,共6页Forging & Stamping Technology

基　　金：重庆市教委科研项目(KJQN201904001)。

摘　　要：为延长5CrNiMo钢热锻模具的服役寿命,提出了喷丸强化工艺。首先,通过喷丸过程的仿真模型和实验验证,确定了最佳喷丸工艺参数,即钢球直径为Φ0.6 mm、喷丸速度为75 m·s^(-1)、覆盖率为150%,并分析了参数对残余应力分布的影响。其次,对比分析了未喷丸处理和最佳工艺参数下喷丸处理后的5CrNiMo钢试样,结果表明,喷丸处理后的试样表面硬度增加了约10%,相比于未喷丸处理试样,喷丸处理试样的摩擦因数显著降低、耐磨损性明显提高。这是由于凹痕吸附的大量石墨形成了石墨隔离层,使得金属表面直接接触面积减小。最后,将最佳喷丸工艺应用于某汽车曲轴终锻模具生产实践,结果表明,未喷丸处理的模具在服役6000件次后表面存在大量的压塌、疲劳裂纹及过量磨损,而喷丸处理后的模具表面未出现这些缺陷,寿命提高约50%。To improve the service life of hot forging die for 5CrNiMo steel,a shot peening strengthening process was proposed.Firstly,through the simulation model and experimental verification of shot peening process,the optimal shot peening process parameters were obtained to be the steel ball diameter of 0.6 mm,the initial speed of 75 m·s^(-1) and the coverage rate of 150%,and the influences of parameters on the residual compressive stress distribution were analyzed.Secondly,the samples of 5CrNiMo steel without shot peening and with shot peening under the best process parameters were compared and analyzed.The results show that the surface hardness of samples increases by about 10%after shot peening.Compared with the sample without shot peening,the friction coefficient of the sample with shot peening decreases significantly,and the wear resistance is significantly improved.This is because the large amount of graphite adsorbed by the dent forms a graphite isolation layer,which reduces the direct contact area of metal surfaces.Finally,the optimal shot peening process was applied to the production of an automobile crankshaft final forging die.Production verification shows that there are a large number of collapse,fatigue cracks and excessive wear on the surface of the mold without shot peening treatment after 6000 pieces of service,while these defects do not appear on the surface of the mold after shot peening,and its service life is increased by about 50%.

关 键 词：喷丸强化 5CRNIMO钢 热锻模 耐磨性 服役寿命 

分 类 号：TG178[金属学及工艺—金属表面处理]