34CrNiMo6曲轴热成形工艺研究及优化  被引量:2

Research and optimization of hot forming process of 34CrNiMo6 crankshaft

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作  者:罗应娜[1] LUO Ying-na(School of Mechanical Engineering and Automation,Chongqing Industry Polytechnic College,Chongqing 401120,China)

机构地区:[1]重庆工业职业技术学院机械工程与自动化学院,重庆401120

出  处:《塑性工程学报》2023年第2期70-78,共9页Journal of Plasticity Engineering

基  金:重庆市自然科学基金面上项目(CSTB2022NSCQ-MSX1029);重庆市教育委员会科学技术研究计划青年项目(KJQN202203204)。

摘  要:为提高某八缸曲轴的锻造成形质量,获得材料最佳热加工工艺窗口,提高材料利用率,首先通过等温压缩实验获得了34CrNiMo6钢在不同温度和应变速率下的流变数据,并通过Hansel-Spittel模型进行了多元线性回归近似,获得了34CrNiMo6钢的高精度本构模型。等温压缩实验表明,当应变速率较低、温度较高时,随着应变的增加,应力逐渐上升,到达峰值后缓慢下降并趋于平稳。这是高温下材料的动态回复、动态再结晶软化行为与加工硬化行为共同作用的结果。当应变速率较高、温度较低时,随着应变的增加,应力逐渐上升并趋于平缓。这是由于应变速率较大时,材料发生有限的动态再结晶,其软化效果有限。其次,通过对Hansel-Spittel模型进行微分处理得到了34CrNiMo6钢的热加工图,热加工图表明:在温度为1350 K,应变速率为0.001 s^(-1)时能量耗散率较大,在该温度和应变速率下进行热加工时,材料具有较高的热加工稳定性,其动态回复、再结晶完全,能得到细小均匀的组织。最后基于Hansel-Spittel模型、热加工温度和应变速率,通过有限元仿真技术分析了坯料尺寸和阻力坎、沟结构对成形效果的影响,发现通过增加阻力坎、沟可在保证锻件无锻造缺陷的前提下,使材料利用率从65%提高到78%,并经过生产试制验证了锻造温度、锻造速率、坯料尺寸和阻力坎结构的设计合理性。To improve the forging forming quality of an eight-cylinder crankshaft,obtain the optimal hot working process window of materials and improve the utilization rate of material,firstly,the rheological data of 34CrNiMo6 steel at different temperatures and strain rates were obtained by isothermal compression experiments,and the high-precision constitutive model of 34CrNiMo6 steel was obtained by multiple linear regression approximation with Hansel-Spittel model.Isothermal compression experiments show that when the strain rate is low and the temperature is high,the stress increases gradually with the increase of strain,and then decreases slowly and tends to be stable after reaching the peak value,which is the results of the interaction between dynamic recovery,dynamic recrystallization softening behavior and work hardening behavior of material at high temperature.When the strain rate is high and the temperature is low,the stress increases gradually and tends to be stable with the increase of strain.This is because when the strain rate is large,the material has limited dynamic recrystallization,and its softening effect is limited.Secondly,the hot processing maps of 34CrNiMo6 steel were obtained by differential treatment of Hansel-Spittel model,and the hot processing maps show that when the temperature is 1350 K and the strain rate is 0.001 s^(-1),the energy dissipation rate is large.When the hot working was carried out at this temperature and strain rate,the hot working stability of material is high,and its dynamic recovery and recrystallization are complete,and fine and uniform microstructure can be obtained.Finally,based on Hansel-Spittel model,hot working temperature and strain rate,the influence of blank size and resistance wall and ditch structure on forming effect was analyzed by finite element simulation technology.It is found that the material utilization rate can be increased from 65%to 78%on the premise that the forgings without forging defects can be guaranteed by adding resistance wall and ditch.The design

关 键 词:曲轴锻造 阻力坎 Hansel-Spittel模型 热加工图 

分 类 号:TG316[金属学及工艺—金属压力加工] TG146.4[一般工业技术—材料科学与工程]

 

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