To study the microstructural evolution of pearlite steel subjected to pure rolling and rolling-sliding contact loading, a hypoeutectoid pearlite steel with composition and microstructure similar to BS11 was designed and twin-disc tests of this pearlite steel were performed to simulate the wheel/rail system. After a series of twin-disc tests, optical microscope (OM) observation, scanning electron microscope (SEM) observation, X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure. Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60 μm below the contact surface of the samples after 120000 revolutions. The largest deformation was approximately 200 μm below the contact surface. Under the rolling-sliding contact condition, the nodularization of pearlite within 100 μm below the contact surface was obvious. The microstructure and stress-strain distribution of the area within 2 mm below the contact surface were investigated. The distribution of micro-hardness under the contact surface varied with contact conditions. Finite element method (FEM) was used to simulate the stress-strain distribution. The results of SEM, FEM, and micro-hardness tests indicated that under the pure rolling contact condition, the maximum plastic strain was approximately 200-400 μm below the contact surface. Conversely, under the rolling-sliding contact condition, the maximum plastic strain emerged on the contact surface. Under the pure rolling contact condition, the distribution of micro-hardness was almost identical to that of the equivalent plastic strain. Under the rolling-sliding contact condition, the distribution of micro-hardness was affected by the equivalent plastic strain and tangential stress.
Abstract
To study the microstructural evolution of pearlite steel subjected to pure rolling and rolling-sliding contact loading, a hypoeutectoid pearlite steel with composition and microstructure similar to BS11 was designed and twin-disc tests of this pearlite steel were performed to simulate the wheel/rail system. After a series of twin-disc tests, optical microscope (OM) observation, scanning electron microscope (SEM) observation, X-ray diffraction (XRD), and micro-hardness tests were conducted to characterize the microstructure. Under the pure rolling contact condition, a large amount of reticular cracks emerged within 60 μm below the contact surface of the samples after 120000 revolutions. The largest deformation was approximately 200 μm below the contact surface. Under the rolling-sliding contact condition, the nodularization of pearlite within 100 μm below the contact surface was obvious. The microstructure and stress-strain distribution of the area within 2 mm below the contact surface were investigated. The distribution of micro-hardness under the contact surface varied with contact conditions. Finite element method (FEM) was used to simulate the stress-strain distribution. The results of SEM, FEM, and micro-hardness tests indicated that under the pure rolling contact condition, the maximum plastic strain was approximately 200-400 μm below the contact surface. Conversely, under the rolling-sliding contact condition, the maximum plastic strain emerged on the contact surface. Under the pure rolling contact condition, the distribution of micro-hardness was almost identical to that of the equivalent plastic strain. Under the rolling-sliding contact condition, the distribution of micro-hardness was affected by the equivalent plastic strain and tangential stress.
关键词
twin-disc test /
rail /
microhardness /
plastic strain /
finite element method
{{custom_keyword}} /
Key words
twin-disc test /
rail /
microhardness /
plastic strain /
finite element method
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1]D.F. Cannon,KO. Edel,S. L. Grassie,K. Sawley,Rail defects: an overview[J].Fatigue & Fracture of Engineering Materials & Structures, 2003, 26(10):865-886
[2]W.R. Tyfour,JH. Beynon,A. Kapoor,The steady state wear behaviour of pearlitic rail steel under dry rolling-sliding contact conditions[J].Wear, 1995, 180(1):79-89
[3]M. Pletz, W. Daves, W. Yao, W. Kubina, S. Scheriau.Multi-scale finite element modeling to describe rolling contact fatigue in a wheel–rail test rig[J][J].Tribology International, 2014, 80 (1):147--155
[4]P.Clayton,Tribological aspects of wheel-rail contact: a review of recent experimental research[J].Wear, 1996, 191(1):170-183
[5]Fang H-S, Liu D-Y, Chang K-D, Zhang C, et al.Microstructure and properties of 1 500 MPa economical bainitemartensite duplex phase steel[J].Journal of Iron and Steel Research, 2001, 13(3):31-36
[6] C. Chattopadhyay, S. Sangal, K. Mondal, A. Garg.Improved wear resistance of medium carbon microalloyed bainitic steels[J][J].Wear, 2012, 289(1):168-179
[7]Liu Z Q, Miyamoto G, Yang Z G, Zhang C, et al.Direct measurement of carbon enrichment during austenite to ferrite transformation in hypoeutectoid Fe-2Mn-C alloys[J].Acta Materialia, 2013, 61(8):3120-3129
[8]J.Kalousek,DM. Fegredo,E. E. Laufer,The wear resistance and worn metallography of pearlite,bainite and tempered martensite rail steel microstructures of high micro-hardness[J].Wear, 1985, 105(3):199-222
[9]Li Z-D, Yang Z-G, Zhang C, et al.Influence of austenite deformation on ferrite growth in a Fe-C-Mn alloy[J].Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2010, 527(16-17):4406-4411
[10]G.Trummer,KSix,C. Marte,P. Dietmaier,C. Sommitsch,An approximate model to predict near-surface ratcheting of rails under high traction coefficients[J].Wear, 2014, 314(1):28-35
[11]A.Kapoor,A re-evaluation of the life to rupture of ductile metals by cyclic plastic strain[J].Fatigue & fracture of engineering materials & structures, 1994, 17(2):201-219
[12]W.Lojkowski,MDjahanbakhsh,G. Bürkle,et al. Nanostructure formation on the surface of railway tracks[J].Materials Science and Engineering: A, 2001, 303(1):197-208
[13]H.W. Zhang,SOhsaki,S. Mitao,et al. Microstructural investigation of white etching layer on pearlite steel rail[J].Materials Science and Engineering: A, 2006, 421(1):191-199
[14] X. Qin, L. Xie, Q. Wu, .Hardening mechanism of Cr5 backup roll material induced by rolling contact fatigue[J][J].Materials Science and Engineering: A, 2014, 600(1):195-199
[15]R.I. Carroll,JH. Beynon,Rolling contact fatigue of white etching layer: Part 1: Crack morphology[J].Wear, 2007, 262(9):1253-1266
[16]Bolton P J, Clayton P, McEwen I J.Wear of Rail and Tire Steels Under RollingSliding Conditions[J].ASLE TRANSACTIONS, 1982, 25(1):17-24
[17]Donzella G, Faccoli M, Mazzù A, et al.Progressive damage assessment in the near-surface layer of railway wheel–rail couple under cyclic contact[J].Wear, 2011, 271(1):408-416
[18]Garnham J E, Davis C L.Very early stage rolling contact fatigue crack growth in pearlitic rail steels[J].Wear, 2011, 271(1):100-112
[19]Garnham J E, Davis C L.The role of deformed rail microstructure on rolling contact fatigue initiation[J].Wear, 2008, 265(9):1363-1372
[20]Y.Ivanisenko,WLojkowski,R. Z. Valiev,et al. The mechanism of formation of nanostructure and dissolution of cementite in a pearlitic steel during high pressure torsion[J].Acta Materialia, 2003, 51(18):5555-5570
[21]R.Halama,RFajko?,P. Matu?ek,et al. Contact defects initiation in railroad wheels–Experience,experiments and modelling[J].Wear, 2011, 271(1):174-185
[22] Liu W B, Zhang C, Xia Z X, et al.Strain-induced refinement and thermal stability of a nanocrystalline steel produced by surface mechanical attritiontreatment[J][J].Materials Science and Engineering: A, 2013, 568 (1):176-183
[23]Xia Z X, Zhang C, Yang Z G.Control of precipitation behavior in reduced activation steels by intermediate heat treatment[J].Materials Science and Engineering: A, 2011, 528(22):6764-6768
[24] Seo J W, Kwon S J, Lee D H, et al.Analysis of contact fatigue crack growth using twin-disc tests and numerical evaluations[J].[J].International Journal of Fatigue, 2013 , 55 (1):54-63
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
This work was financially supported by National Basic Research Programs of China;This work was financially supported by National Basic Research Programs of China
{{custom_fund}}