EBSM成形24CrNiMo合金钢组织演变和摩擦磨损性能  

Microstructure evolution and tribology performance of 24CrNiMo steel manufactured by EBSM

作　　者：王岩 郑浩 高军恒 魏瑛康 王建勇 张亮亮 贾文鹏 刘世锋[1] WANG Yan;ZHENG Hao;GAO Junheng;WEI Yingkang;WANG Jianyong;ZHANG Liangliang;JIA Wenpeng;LIU Shifeng(School of Metallurgical and Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,Shaanxi,China;Innovation Research Institute Carbon Neutrality,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055 [2]北京科技大学碳中和创新研究院,北京100083

出　　处：《钢铁》2024年第8期169-180,199,共13页Iron and Steel

基　　金：国家自然科学基金资助项目(52104341,52304357,52304384);陕西省科技厅杰出青年科学基金资助项目(2024JC-JCQN-52)。

摘　　要：24CrNiMo合金钢具有优异的强韧性、淬透性和耐磨性,广泛应用于高速列车制动盘。铸锻造制备高速列车制动盘存在铸造缺陷、成品率低、成形结构受到限制等问题。电子束选区熔化(electron beam selective melting,EBSM)是一种以电子束为能量源,逐点、逐线、逐面扫描堆叠,成形三维实体的金属增材制造技术,对成形结构复杂、加工困难、精度高的零件一体化制备有着天然优势,可制备出晶粒尺寸细小、成分均匀、力学性能优异的金属材料。通过电子束选区熔化制备了24CrNiMo合金钢,探讨了在不同工艺参数下对试样致密度、显微组织、硬度和摩擦磨损的影响规律。研究结果表明,随着能量密度的增加,致密度有先增大后减小的趋势。在电流流束为13 m A、扫描速度为5 m/s的工艺参数下成形试样的致密度和硬度最高,分别达到98.96%和355HV0.3。EBSM成形的24CrNiMo合金钢的显微组织主要由粒状贝氏体(GB)和准贝氏体(Bm)组成,基体为贝氏体铁素体(BF)。随着能量密度的增大,热输入增加,晶粒取向由随机分布向(101)和(001)方向优先织构,晶粒尺寸逐渐增大,残余奥氏体含量增多。摩擦磨损试验发现能量密度为39 J/mm^(3)的成形试样具有最高的耐磨性。磨损机制主要为黏着磨损和磨粒磨损。残余奥氏体含量和缺陷是造成摩擦磨损性能不同的主要原因。为后续开展EBSM制备制动盘提供了一定的基础研究和理论指导。24CrNiMo alloy steel has excellent toughness,hardenability and wear resistance,and is widely used in high-speed train brake discs.There are some problems such as casting defects,low yield and limited forming structure of brake discs prepared by casting and forging.electron beam selective melting(EBSM)is a metal additive manufacturing technology using electron beam as energy source,scanning and stacking point by point,line by line and surface by surface to form three-dimensional entity,which has natural advantages for the integrated preparation of parts with complex forming structure,difficult processing and high precision.Metal materials with fine grain size,uniform composition and excellent mechanical properties can be prepared.24CrNiMo alloy steel was prepared by electron beam selective melting.The influence of different process parameters on the density,microstructure,hardness and friction wear of the sample was investigated.The results show that the density increases first and then decreases with the increase of energy density.Under the process parameters of current beam 13 mA and scanning speed 5 m/s,the density and hardness of the formed samples are the highest,reaching 98.96%and 355HV0.3,respectively.The microstructure of 24CrNiMo alloy steel formed by EBSM is mainly composed of granular bainite(GB)and interbainite(Bm),and the matrix is bainitic ferrite(BF).With the increase of energy density,the heat input increases,the grain orientation changes from random distribution to(101)and(001)direction,the grain size increases gradually,and the residual austenite content increases.The friction and wear test shows that the shaped sample with energy density of 39 J/mm^(3) has the highest wear resistance.The main wear mechanisms are adhesive wear and abrasive wear.Residual austenite content and defects are the main reasons for the difference in friction and wear properties.This experiment provides some basic research and theoretical guidance for the subsequent development of EBSM brake disc preparation.

关 键 词：低碳合金钢 增材制造 工艺参数 显微组织 摩擦磨损 

分 类 号：TG142.33[一般工业技术—材料科学与工程]