动车组车轮异常组织特征及成因  

Characteristics and Causes of Abnormal Microstructure in EMU Wheels

作　　者：张关震 任瑞铭[2] 尹鸿祥[1] 吴斯 丛韬 王浩 李冬玲[4] ZHANG Guanzhen;REN Ruiming;YIN Hongxiang;WU Si;CONG Tao;WANG Hao;LI Dongling(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;School of Material Science and Engineering,Dalian Jiaotong University,Dalian Liaoning 116028,China;School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Gangyan Nake Inspection&Testing Technology Corporation Limited,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081 [2]大连交通大学材料科学与工程学院,辽宁大连116028 [3]北京科技大学材料科学与工程学院,北京100083 [4]钢研纳克检测技术股份有限公司,北京100081

出　　处：《中国铁道科学》2020年第4期108-115,共8页China Railway Science

基　　金：中国国家铁路集团有限公司科技研究开发计划项目(J2018J004,J2019J004);中国铁道科学研究院集团有限公司科研开发基金项目(2019YJ093)。

摘　　要：针对存在异常组织的动车组车轮,利用光学显微镜、高分辨透射电镜观察车轮微观组织形貌,利用激光诱导击穿光谱分析仪测试踏面区域合金元素分布,利用JMatPro软件模拟等温转变曲线,利用热膨胀仪实测连续冷却转变曲线,分析异常组织的类型、特征和成因。结果表明:车轮中的异常组织为上贝氏体,呈条带状分布在车轮踏面处,且随着踏面深度的增加,其占比不断减小;车轮局部微区碳元素的严重偏析是导致上贝组织形成的主要原因,它使得等温转变曲线明显向右偏移,增大偏析区域处组织在较高冷速下向贝氏体转变的概率,导致车轮实际生产中更多的贝氏体组织聚集在冷速最高的踏面局部区域;车轮整体过高的钒元素使连续冷却转变曲线发生右移,其中贝氏体转变区右移程度更大,明显降低贝氏体组织转变开始时的冷速,增大实际生产中车轮贝氏体组织的形成深度。In order to investigate the types,characteristics and causes of abnormal microstructure in EMU wheels,the microstructure morphology of EMU wheels with abnormal microstructure was observed by optical microscope and high resolution transmission electron microscopy.The distribution of alloying elements in tread area was measured by laser induced breakdown spectroscopy analyzer.The isothermal transformation curve was simulated by JMatPro software,and the transformation curve of continuous cooling was measured by thermal expansion instrument.Results show that the abnormal microstructure in the wheel is upper bainite,which is distributed in strips in the wheel tread,and its content decreases with the increase of tread depth.The serious segregation of carbon(C)element in the local micro-area of wheel is the main reason for the formation of upper bainite.The segregation of carbon element makes the isothermal transformation curve shift to the right obviously,which increases the probability of the bainite transformation in the segregation area at a higher cooling rate,and leads to more bainite gathering in the local area of the tread with the highest cooling rate in the actual production of wheels.The high content of vanadium(V)element in the whole wheel makes the continuous cooling transition curve shift to the right.Among them,the bainite transition zone shifts to the right more,which significantly reduces the cooling rate of bainite transformation at the beginning and increases the formation depth of bainite microstructure in the wheel during the actual production.

关 键 词：动车组 车轮 异常组织 上贝氏体 偏析 合金元素 

分 类 号：U266[机械工程—车辆工程]