铁路扣件弹条用60Si2Mn弹簧钢力学性能试验研究  

Experimental study on mechanical properties of 60Si2Mn spring steel for railway fastener clips

作　　者：闫子权 孙林林 肖俊恒 王亚洲 刘炳彤 崔树坤 YAN Ziquan;SUN Linlin;XIAO Junheng;WANG Yazhou;LIU Bingtong;CUI Shukun(State Key Laboratory of Track Technology for High Speed Railway,Beijing 100081,China;Railway Engineering Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;Beijing Tieke Shougang Railway-Tech Co.,Ltd.,Beijing 102206,China)

机构地区：[1]高速铁路轨道技术国家重点实验室,北京100081 [2]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081 [3]北京铁科首钢轨道技术股份有限公司,北京102206

出　　处：《铁道科学与工程学报》2023年第1期127-135,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52178441);中国铁道科学研究院集团有限公司科研项目(2021YJ069)。

摘　　要：弹条是扣件系统最重要的零部件之一,通过弹条自身的弯曲和扭转变形产生扣压力作用在钢轨上,有效地保证钢轨和轨下基础结构之间的可靠连接。60Si2Mn热轧弹簧钢是我国生产扣件弹条的最主要的材料,但目前尚无该材料的疲劳极限及疲劳性能曲线等关键参数。针对当前铁路扣件弹条常用的60Si2Mn弹簧钢进行基本力学性能和疲劳性能试验,采用弹条生产工艺热处理的60Si2Mn弹簧钢标准试件,根据GB/T 228.1―2010中的金属材料拉伸试验方法进行单轴静力拉伸试验得到基本静力性能,其弹性模量约为201 GPa,屈服强度约为1 293 MPa,断裂强度约为1 430 MPa。采用成组试验法对试件进行应力比R=-1下4级试验应力水平的疲劳试验,并采用升降法对试件进行应力比为R=-1条件下5级试验应力水平的疲劳试验,得到不同应力水平下的疲劳寿命和指定寿命为107循环下的疲劳极限,60Si2Mn弹簧钢的中值疲劳极限为740 MPa。根据对数疲劳寿命符合正态分布的假设,通过最小二乘法分别对不同可靠度下的疲劳极限数据进行拟合,得到60Si2Mn弹簧钢的疲劳寿命和安全寿命曲线,其60Si2Mn弹簧钢的中值寿命曲线为(lg N)_(50)=9.334 4-2.142 4lg(S_(max)-740),可靠度为99%的安全寿命曲线为(lg N)_(99)=8.740 0-2.056 5lg(S_(max)-697)。本文采用的S-N曲线描述方法可以覆盖60Si2Mn弹簧钢的中、长寿命区,能更准确地反映弹条真实力学性能,为弹条疲劳损伤断裂机理及寿命预估提供更为可靠的试验数据。The clip is one of the most important components of the fastening system. Through the bending and torsion deformation of the clip, the buckle pressure acts on the rail, effectively ensuring the reliable connection between the rail and the underrail infrastructure. The 60Si2Mn hot-rolled spring steel is the most important material produced in China, but there are no key parameters such as the fatigue limit and fatigue performance curve of this material. Basic mechanical performance and fatigue performance testswere conducted for 60Si2Mn spring steel. Firstly, 60Si2Mn spring steel was obtained by uniaxial tensile tests of metal materials in GB/T 228.1―2010, with elastic modulus of about 201 GPa, yield strength of about 1 293 MPa and fracture strength of about 1 430 MPa. Secondly, the group test method is used for fatigue test of level 4 under R=-1 and the up-and-down fatigue test with stress of level 5 under R=-1, so that the fatigue life and specified life of 107 cycle, and the median fatigue limit of 60Si2Mn spring steel is 740 MPa. Finally, according to the assumption that log fatigue life meets normal distribution, the fatigue life curve of the spring steel of 60Si2Mn, whose median life curve was(lg N)_(50)=9.334 4-2.142 4lg(S_(max)-740) and 99% reliability life was(lg N)_(99)=8.740 0-2.056 5lg(S_(max)-697). The SN curve description method adopted in this paper can cover the medium and long-life areas of 60Si2Mn spring steel, which can more accurately reflect the real mechanical properties of the clip. The results can provide more reliable test data for the clip fatigue damage fracture mechanism and life prediction.

关 键 词：扣件弹条 弹簧钢 机械性能 疲劳试验 P-S-N曲线 

分 类 号：U213[交通运输工程—道路与铁道工程]