摘要
以两个直径为600 mm,长度为1800 mm的45Cr4NiMoV圆柱形试验件为研究对象,对其进行了部分硬化淬回火热处理,在其中一个试验件上进行敷偶测温及宏观金相检测实验,在另一个试验件上应用Sachs法进行残余应力的测量;建立了试验件淬回火过程中的温度、组织、应力演变模型,并验证了模型的准确性。研究了部分硬化大截面轴类件热处理残余应力的演变过程,讨论了材料参数、边界条件对有限元模拟残余应力分布结果的影响。结果表明,模拟与实测应力吻合较好,试验件由于尺寸较大整体呈现出表面压心部拉的热应力型分布特征,淬硬层附近呈现出内压外拉的相变应力特征。马氏体转变温度降低、膨胀系数降低、相变塑性增大使工件心部应力减小,表面应力增大;换热系数增大,则心部应力增大,表面应力降低。
Taking two 45 Cr4 NiMoV steel cylindrical samples with size of ?600 mm×1800 mm as the research object, the partial hardening and quenching heat treatment was carried out, the temperature measurement and macroscopic metallographic test were carried out on one of the sample, and the residual stress was measured by Sachs method on the other sample. The model of temperature, microstructure and stress evolution of the partial hardened 45 Cr4 NiMoV steel cylindrical sample during quenching and tempering was established, and the accuracy of the model was verified by experiment. The evolution process of heat treatment residual stress in partially hardened large-section backup roll was studied, and the influence of material parameters and boundary conditions on the results of finite element simulation of residual stress distribution was discussed. The results show that the simulated stress is in good agreement with the measured stress. Because of the large size of the sample, the residual stress distribution of the whole sample is characterized by the thermal stress distribution characteristics, which is compressive stress at the surface and tensile stress at the center, and the residual stress distribution near the hardened layer is characterized by phase transformation stress distribution characteristics, which is compressive stress at the center and tensile stress at the surface. The decrease of martensitic transformation temperature and expansion coefficient and the increase of phase transformation plasticity will lead to the decrease of the center stress and the increase of the surface stress of the sample. With the increase of heat transfer coefficient, the center stress of the sample increases and the surface stress decreases.
作者
张雪姣
杨康
李萌蘖
宋肖阳
朱琳
ZHANG Xue-jiao;YANG Kang;LI Meng-nie;SONG Xiao-yang;ZHU Lin(Tianjin Heavy Equipment R&D Co Ltd,Tianjin 300457,China;School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2021年第5期170-177,共8页
Transactions of Materials and Heat Treatment
基金
天津市科技支撑重点项目(17YFZCGX00900)。
关键词
数值模拟
热处理
残余应力
支承辊
Sachs法
finite element simulation
heat treatment
residual stress
backup roll
Sachs’boring method
