Study on Ratcheting Behavior of Flash Butt Welds in U71Mn Rail

doi:10.3901/JME.2025.08.116

Abstract

Abstract: The ratcheting behavior induced by cyclic load is the main cause of rail rolling contact fatigue (RCF), especially the softened zone of rail welded joint is more sensitive to RCF. The uniaxial stress control cycle tests were performed to investigate the ratcheting behaviour of the central zone (the bond line +the highest hardness zone) and the softened zone in a flash butt welds joint and the base metal. The results show that the central zone and the softened zone exhibit obvious ratcheting behavior under the cyclic load of asymmetric stress. The increase of average stress and stress amplitude will lead to the increase of ratcheting strain, and the influence of stress amplitude on ratcheting strain is greater than that of average stress. The softened zone with the lowest hardness has the lowest ratchet resistance. The spheroidal structure on the softened zone reduces the strength and increases the sensitivity of the ratchet.Thus reduces the life of the softened zone. The central area has the highest ratchet resistance, but its life is shortest due to the presence of non-metallic inclusions.The relationship between fatigue life and the ratcheting strain in the three regions is not uniform, and the fatigue life is paired with the stable the ratcheting strain rate of each region, and the life decreases with the increase of the ratcheting strain only for one region. The research results can provide the material parameters for the constitutive model of the rail welded joints.

Key words: U71Mn rail flash butt welds, ratcheting behaviour, cyclic load, fracture analysis

CLC Number:

O341

JIANG Wenjuan, WANG Wenjian, DING Haohao, LIU Qiyue. Study on Ratcheting Behavior of Flash Butt Welds in U71Mn Rail[J]. Journal of Mechanical Engineering, 2025, 61(8): 116-126.

References

[1] PUN C L，KAN Q H，MUTTON J P，et al. An efficient computational approach to evaluate the ratcheting performance of rail steels under cyclic rolling contact in service[J]. International Journal of Mechanical Sciences，2015，101-102：214-226.
[2] WEN Z F，WU L，LI W，et al. Three-dimensional elastic- plastic stress analysis of wheel-rail rolling contact[J]. Wear，2011，271(1)：426-436.
[3] RINGSBERG W J. Rolling contact fatigue of railway rails with emphasis on crack initiation[D]. Gothenburg：Chalmers University of Technology，2000.
[4] 梁喜仁，陶功权，陆文教，等. 地铁钢轨滚动接触疲劳损伤研究[J]. 机械工程学报，2019，55(2)：147-155. LIANG Xiren，TAO Gongquan，LU Wenjiao，et al. Study on the rail rolling contact fatigue of subway[J]. Journal of Mechanical Engineering，2019，55(2)：147-155.
[5] TYFOUR W，BEYNON J，KAPOOR A. Deterioration of rolling contact fatigue life of pearlitic rail steel due to dry-wet rolling-sliding line contact[J]. Wear，1996，197(1)：255-265.
[6] KAPOOR A. Wear by plastic ratchetting[J]. Wear，1997，212(1)：119-130.
[7] TYFOUR W R，BEYNON J H. The effect of rolling direction reversal on the wear rate and wear mechanism of pearlitic rail steel[J]. Tribology International，1994，27(6)：401-412.
[8] DING H H，FU Z K，WANG W J，et al. Investigation on the effect of rotational speed on rolling wear and damage behaviours of wheel/rail materials[J]. Wear，2015，330：563-570.
[9] FRANKLIN F J，CHUNG T，KAPOOR A. ratcheting and fatigue-led wear in rail-wheel contact[J]. Fatigue and Fracture of Engineering Materials & Structures，2003，26(10)：949-955.
[10] UEDA M，MATSUDA K. Effects of carbon content and hardness on rolling contact fatigue resistance in heavily loaded pearlitic rail steels[J]. Wear，2019，444-445(3)：203120.
[11] ATHUKORALA A C，PELLEGRIN D V D，KOUROUSIS K I. A unified material model to predict ratcheting response in head-hardened rail steel due to non-uniform hardness distributions[J]. Tribology International，2017，111：26-38.
[12] MCDOWELL D L. Stress state dependence of cyclic ratcheting behaviour of two rail steels[J]. International Journal of Plasticity，1995，11(4)：397-421.
[13] PUN C L，KAN Q H，MUTTON J P，et al. ratcheting behaviour of high strength rail steels under biaxial compression-torsion loadings experiment and simulation[J]. International Journal of Fatigue，2014，66：139-154.
[14] KHODDAM S，SHAMDANI A H，MUTTON P，et al. A new test to study the cyclic hardening behaviour of a range of high strength rail materials[J]. Wear，2014，313(1-2)：43-52.
[15] ATHUKORALA A C，DE P D V，KOUROUSIS K L. Characterisation of head-hardened rail steel in terms of cyclic plasticity response and microstructure for improved material modelling[J]. Wear，2016，366：416-424.
[16] 时丕顺. 高速列车曲线通过时U75V钢轨滚动接触疲劳研究[D]. 成都：西南交通大学，2021. SHI Pishun. Study on rolling contact fatigue of U75V rail during curve passing of high-speed train[D]. Chengdu：Southwest Jiaotong University，2021.
[17] KANG G Z，GAO Q，YANG X J. Experimental study on the cyclic deformation and plastic flow of U71Mn rail steel[J]. International Journal of Mechanical Sciences，2002，44(8)：1647-1663.
[18] KANG G Z，GAO Q. Uniaxial and non-proportionally multiaxial ratcheting of U71Mn rail steel：experiments and simulations[J]. Mechanics of Materials，2002，34(12)：809-820.
[19] KANG G Z GAO Q，CAI L X，et al. Experimental study on non-proportional multiaxial strain cyclic characteristics and ratcheting of U71Mn rail steel[J]. Journal of Materials Science & Technology，2002，18(1)：13-16.
[20] 康国政，高庆. 循环稳定材料的棘轮行为：I. 实验和本构模型[J]. 工程力学，2005(2)：206-211. KANG Guozheng，GAO Qing. Ratcheting of cyclically stable materials：I. experiments and a visco-plastic constitutive model[J]. Engineering Mechanics，2005(2)：206-211.
[21] 樊译璘，阚前华，康国政，等. 热处理U71Mn钢轨钢的棘轮行为及其本构模型[J]. 机械工程材料，2019，43(11)：62-67. FAN Yilin，KAN Qianhua，KANG Guozheng，et al. Ratcheting behavior and constitutive model of heat-treated U71Mn rail steel[J]. Materials for Mechanical Engineering，2019，43(11)：62-67.
[22] 樊译璘，阚前华，赵吉中，等. 不同钢轨材料棘轮行为试验研究[J]. 机械工程学报，2020，52(2)：35-42. FAN Yilin，KAN Qianhua，ZHAO Jizhong，et al. Experimental study on ratcheting behavior of different rail steels[J]. Journal of Mechanical Engineering，2020，52(2)：35-42.
[23] 牛小革，罗欢，朱君，等. 钢轨闪光对焊接头的组织和韧性[J]. 热加工工艺，2015，44(5)：187-190. NIU Xiaoge，LUO Huan，ZHU Jun，et al. Microstructure and toughness in flash-butt welded joint of rail steel[J]. Hot Working Technology，2015，44(5)：187-190.
[24] 蒋文娟，王文健，丁昊昊，等. U71Mn钢轨气压焊接头的损伤行为[J]. 机械工程材料，2021，45(2) ：43-48. JIANG Wenjuan，WANG Wenjian，DING Haohao，et al. Damage behavior of U71Mn steel rail gas pressure welded joint[J]. Materials for Mechanical Engineering，2021，45(2)：43-48.
[25] PORCARO R R，FARIA G L，GODEFROID L B，et al. Microstructure and mechanical properties of a flash butt welded pearlitic rail[J]. Journal of Materials Processing Technology，2019，270：20-27.
[26] MANSOURI H，MONSHI A. Microstructure and residual stress variations in weld zone of flash-butt welded railroads[J]. Science and Technology of Welding and Joining，2004，9(3)：237-245.
[27] MUTTON P，COOKSON J，QIU C，et al. Microstructural characterization of rolling contact fatigue damage in flashbutt welds[J]. Wear，2016，366-367：368-377.
[28] SU H，PUN C L，MUTTON P，et al. Numerical study on the ratcheting performance of rail flash butt welds in heavy haul operations[J]. International Journal of Mechanical Sciences，2021，199：106434.
[29] WU Y，LUN P C，SU H，et al. Numerical study on ratcheting performance of heavy haul rail flash-butt welds in curved tracks[J]. Engineering Failure Analysis，2022：140.
[30] 金学松，郭俊，肖新标，等. 高速列车安全运行研究的关键科学问题[J]. 工程力学，2009(S2)：8-22. JIN Xuesong，GUO Jun，XIAO Xinbiao，et al. Key scientific problems in the study on running safety of high speed trains[J]. Engineering Mechanics，2009(S2)：8-22.
[31] 康国政，高庆. 棘轮行为及其本构模型和工程应用的研究进展[J]. 应用力学学报，2008(3)：455-461，543. KANG Guozheng，GAO Qing. Advances of ratcheting in cyclic constitutive models applications[J]. Chinese Journal of Applied Mechanics，2008(3)：455-461，543.
[32] 王莹莹. 钢轨闪光焊接头灰斑和微裂纹缺陷形成机理研究[D]. 北京：中国铁道科学研究院，2018. WANG Yingying. Research on formation mechanism of flat spots and micro-crack defects in rail welded joints[D]. Beijing：China Academy of Railway Sciences，2018.