43 kg/m爬坡式尖轨的离线热处理  

Off-line heat treatment of 43 kg/m climbing switch rail

作　　者：杨含[1] 兰超锋 王雄[1] 万静斌 Yang Han;Lan Chaofeng;Wang Xiong;Wan Jingbin(China Railway Baoji Bridge Group Co.,Ltd.,Baoji Shaanxi 721006,China)

机构地区：[1]中铁宝桥集团有限公司,陕西宝鸡721006

出　　处：《金属热处理》2024年第9期204-208,共5页Heat Treatment of Metals

基　　金：中铁宝桥集团有限公司自立科研项目(JK31-14)。

摘　　要：为提升材质为U71Mn钢的43 kg/m爬坡式尖轨离线热处理后的整体性能,避免热处理过程中尖轨小断面台阶处打火缺陷,通过改变机加工顺序和加工量,以及针对不同断面长度区间,采用不同车速和风压的欠速淬火热处理方式,对热处理后的尖轨表面硬度、断面硬度和硬化层形貌及显微组织进行检测分析。结果表明,采用从尖端至35 mm断面统一按35 mm断面尺寸加工,35 mm断面至跟端按成品尺寸加工,热处理后再机加工到成品尺寸的改进工艺后,小断面硬度有了较大的提高,断面硬度达到32.0~34.5 HRC,显微组织为珠光体+少量铁素体,无马氏体、贝氏体等异常组织,并消除了打火缺陷,完全满足相关要求。In order to improve the overall performance of 43 kg/m climbing switch rail made of U71Mn steel after off-line heat treatment and avoid the spark defect at the small section step of switch rail during heat treatment,by changing the machining sequence and processing quantity,as well as using underspeed quenching heat treatment methods with different vehicle speeds and wind pressures for different section length ranges,the surface hardness,section hardness,morphology of hardened layer and microstructure of the heat-treated switch rail were tested and analyzed.The results show that after adopting the improved process of processing from the tip to the 35 mm section according to the 35 mm section size,processing from the 35 mm section to the heel end according to the finished product size,and then machining to the finished product size after heat treatment,the hardness of the small section significantly improves,reaching 32.0-34.5 HRC.Microstructure consisted of pearlite and a small amount of ferrite,without any abnormal structures such as martensite or bainite,and eliminated spark defects,fully meeting the relevant requirements.

关 键 词：U71Mn钢 爬坡式尖轨 离线热处理 机加工 

分 类 号：TG156.33[金属学及工艺—热处理]