中国机械工程

• • 上一篇    下一篇

[表面强化及损伤机理]钢轨表面宽带激光淬火工艺及其疲劳磨损性能

杨志翔1;王爱华1;熊大辉1;张琨2;罗小华2   

  1. 1.华工激光工程有限责任公司,武汉,430223
    2.中铁第四勘察设计院集团有限公司,武汉,430063
  • 出版日期:2019-02-10 发布日期:2019-02-18
  • 基金资助:
    国家重点研发计划资助项目(2016YFB1102700)

Lser Wide-band Hardening of Steel Rails and Corresponding Fatigue Wear Property

YANG Zhixiang1;WANG Aihua1;XIONG Dahui1;ZHANG Kun2;LUO Xiaohua2   

  1. 1.Wuhan Huagong Laser Engineering Co.,Ltd.,Wuhan,430223
    2.China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,430063
  • Online:2019-02-10 Published:2019-02-18

摘要: 针对目前钢轨强化采用的欠速淬火方法存在强化层硬度偏低、耐磨性难以满足重载线路使用要求的问题,使用3种不同光斑宽度的激光,研究了U71Mn材质钢轨的激光淬火强化工艺,获得了不同扫描速度下的临界功率和淬火层深,并测试了淬火层在滚动接触条件下的磨损与接触疲劳性能。结果表明:在临界熔化的激光能量密度下,光斑宽度由6 mm增加到20 mm时,淬火层深度提高了38%,或在获得相同的淬火层深度情况下,处理效率提高6.8倍;淬火层组织为针状马氏体,硬度从原来的300HV提高到800HV以上;20万周次的磨损试验后,激光淬火试样的磨损量只有未处理试样磨损量的25%,未处理试样以表面接触疲劳剥落和塑性变形为主,激光淬火试样仅有轻微的疲劳磨损,耐磨性和抗接触疲劳性能优异。

关键词: 钢轨, 激光淬火, 滚动接触疲劳, 磨损

Abstract: Nowadays, online slack quenching technique was widely used for the hardening of steel rails, but the hardness of hardened layers was relatively low and was insufficient to meet the wear resistance demands of heavy-haul railways. Laser hardening process was carried out on U71Mn rail surfaces by utilizing rectangle laser beam size with three different widths. The critical laser powers and hardened layer depths at different scanning velocities were obtained for the three different laser beam sizes. Furthermore, the wear and rolling contact fatigue property of laser-hardened layers were also investigated. Results show that under the same critical laser powers, the increase of laser beam widths from 6 mm to 20 mm results in a significant increase in hardened depths(about 38%) or productivity (about 6.8 times); the microstructures of the laser-hardened layers are composed of acicular martensite and have a much higher microhardness of 800HV in comparison with that of the original steel rails(about 300HV); the weight losses of laser-hardened specimens are only 25% of the untreated ones after 200 thousand cycle RCF tests; the damaged surfaces display severe contact fatigue spalling and plastic deformations for the untreated specimens but only slight fatigue wear for the laser-hardened specimens, which indicate the outstanding wear and RCF resistances for the laser-hardened rails.

Key words: steel rail, laser hardening, rolling contact fatigue(RCF), wear

中图分类号: