20MnCrS5真空低压渗碳气淬多场耦合模拟分析  

Multi-field Coupling Simulation Analysis of 20MnCrS5 Vacuum Low Pressure Carburizing and Gas Quenching

作　　者：张泽宇 邓小虎[1] 凡园园 王会珍 周乐育 徐跃明 巨东英 ZHANG Zeyu;DENG Xiaohu;FAN Yuanyuan;WANG Huizhen;ZHOU Leyu;XU Yueming;JU Dongying(School of Mechanical Engineering,Tianjin Vocational and Technical Normal University,Tianjin 300222,China;Ningbo Tian'an(Group)Co.,Ltd.,Zhejiang Ningbo 315700,China;Beijing Institute of Mechanical and Electrical Engineering Co.,Ltd.,Beijing 100083,China;Saitama Institute of Technology,Fukaya 3690293,Japan)

机构地区：[1]天津职业技术师范大学机械工程学院,天津300222 [2]宁波天安(集团)股份有限公司,浙江宁波315700 [3]北京机电研究所有限公司,北京100083 [4]埼玉工业大学,日本深谷3690293

出　　处：《表面技术》2024年第15期194-205,共12页Surface Technology

基　　金：江苏省产学研合作项目(BY2022834);天津市研究生科研创新项目(2022SKYZ161);国家重点研发计划项目(2018YFE0207000);大学生创新创业训练计划项目(202310066162)。

摘　　要：目的采用试验研究、模拟计算和理论分析相结合的手段,对20MnCrS5齿轮钢真空低压渗碳过程的组织性能演变机理进行研究。方法引入符合真空渗碳强渗、扩散交替进行的扩散边界条件,并修正硬度计算方程,开发真空低压渗碳高压气淬过程仿真模型。分别建立ϕ15mm×100mm圆棒试样二维轴对称和三维实体有限元模型,对20MnCrS5圆棒试样不同工艺参数下真空渗碳过程进行模拟仿真,开展真空渗碳试验与仿真分析化研究。结果二维轴对称模型和三维实体模型计算精度接近,可以代替三维模型,提高计算效率。不同工艺参数真空渗碳过程得到的模拟和试验结果吻合较好,验证了改进模型和方程的可用性,并对不同工艺条件下碳浓度、组织和性能演变规律进行了研究。而后将模型应用到德国FZG(Forschungsstelle für Zahnräder und Getriebebau)标准齿轮样件,对其真空渗碳过程进行了模拟,结果可较好地反映齿轮不同位置碳浓度分布的特点,进一步验证了模型的准确性。结论通过本研究,揭示了20MnCrS5齿轮钢真空低压渗碳过程的组织性能演变机理,并为复杂零部件真空渗碳过程工艺开发提供了新的思路。Vacuum low-pressure carburizing stands as an advanced surface heat treatment technique,conferring strengthened casing with heightened fatigue resistance to transmission gears.In this study,a comprehensive approach,encompassing experimental research,computational simulations,and theoretical analysis were adopted to scrutinize the microstructural evolution within the vacuum low-pressure carburizing process of 20MnCrS5 gear steel.A multi-field coupling model,considering the synergistic effects of temperature,concentration,phase transformation,and stress,was introduced to simulate the vacuum carburizing process specific to 20MnCrS5 steel.The carbon diffusion model was used to incorporate the growth kinetics of carbide phases and compute concentration-dependent diffusion coefficients.The phase transformation behavior was characterized using the Johnson-Mehl-Avrami equation.Simulating the quenching process involved determining the heat convection coefficient based on an inverse analysis of cooling curves.Complex diffusion boundary conditions were implemented to depict alternating carburization and diffusion during industrial vacuum carburizing.Furthermore,diffusion boundary conditions were established to simulate the inherent alternating diffusion and strong carburization in vacuum carburizing.Corrections were applied to hardness calculation equations,and a simulation model was developed for the vacuum low-pressure carburizing process,followed by high-pressure gas quenching.It was recognized that three-dimensional models often demanded more nodes and elements,necessitating higher computing resources,a pragmatic approach was explored.In certain scenarios,a two-dimensional model was preferred to enhance computational efficiency.Two finite element models were constructed:one in two-dimensional axisymmetric geometry and the other in three-dimensional solid geometry.These models simulated the vacuum carburizing process for cylindrical rod samples(ϕ15 mm×100 mm)under varying process parameters.Results demonstrated that the

关 键 词：真空渗碳 数值仿真 COSMAP 碳含量 硬度 20MnCrS5齿轮钢 

分 类 号：TG145[一般工业技术—材料科学与工程]