An effect of strength of railway axle steels on fatigue resistance under press fit

Linhart, V.; Černý, Ivo

doi:10.1016/j.engfracmech.2010.11.023

Cited by 45 publications

(21 citation statements)

References 8 publications

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“…In the assemblages using standard surface EA4T steel, the maximum stress at 3 × 10 7 cycles was only 132 MPa. This limit is comparable with the results of fatigue tests on bars made of the same axle material published by Linhart and Černý . The cause of the lower fatigue strength in comparison with the standard is the lower value of the wheel seat diameter/axle body diameter ratio D / d = 1.06.…”

Section: Testing Materials and Experimental Proceduressupporting

confidence: 88%

“…When testing at local test stresses above 400 MPa, it was necessary to air‐cool the test assemblages because the effect of micro‐movements in the area of the press‐fitted joint caused the surface of the seat to heat up to temperatures in excess of 85 °C under heavy loading; fretting damage is initiated above this temperature …”

Section: Testing Materials and Experimental Proceduresmentioning

confidence: 99%

“…This limit is comparable with the results of fatigue tests on bars made of the same axle material published by Linhart and Černý. 22 The cause of the lower fatigue strength in comparison with the standard 26 is the lower value of the wheel seat diameter/axle body diameter ratio D/d = 1.06. The fatigue limit defined in standard EN 13261 26 for the area of the press-fitted joint for EA4T steel is 145 MPa; however, this is for the minimum value of D/d = 1.12.…”

Section: Materials For Axle Manufacture and Its Mechanical Propertiesmentioning

confidence: 99%

“…The fatigue damage tolerance therefore takes into account not only the minimum crack size detectable using NDT methods but also suitable intervals between inspections, set depending on the location and period of operation. In addition to these basic design concepts, studies also focus on the effects of structural materials, surface treatments, methods of heat treatment and subsequent machining, and geometric parameters – particularly the effect of axle body diameter and wheel seat diameter on fatigue strength with a focus on high‐speed train axles . One technology applied to increase axle fatigue strength is surface induction hardening, which involves the relatively rapid heating of surface layers of pre‐machined axles up to the hardening temperature using an inductor, followed by the rapid cooling of the axle by a water jet positioned behind the inductor and also by the transfer of heat by the axle body.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to these basic design concepts, studies also focus on the effects of structural materials, surface treatments, methods of heat treatment and subsequent machining, and geometric parametersparticularly the effect of axle body diameter and wheel seat diameter on fatigue strength with a focus on high-speed train axles. [13][14][15][16][17][18][19][20][21][22] One technology applied to increase axle fatigue strength is surface induction hardening, which involves the relatively rapid heating of surface layers of pre-machined axles up to the hardening temperature using an inductor, followed by the rapid cooling of the axle by a water jet positioned behind the inductor and also by the transfer of heat by the axle body. As a consequence, the fatigue limit is significantly increased, and short fatigue cracks in surface layers are hardly able to propagate.…”

Section: Introductionmentioning

confidence: 99%

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Fatigue limit of induction hardened railway axles

Fajkoš

Zima

Strnadel

2015

Fatigue Fract Eng Mat Struct

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A B S T R A C T A new surface induction hardening technology was designed for the purpose of increasing the resistance of railway wheelsets to fatigue damage. This paper gives a detailed presentation of the technological aspects of induction hardening of axles. The increased fatigue resistance in hardened surfaces compared with standard heat treatment of EA4T steel was verified using tensile test specimens, press-fitted wheel seat/axle joints at 1:3 scale and press-fitted wheel/axle joints at actual size. The 70% increase in the fatigue limit of induction hardened EA4T steel specimens compared with material subjected to standard heat treatment clearly demonstrates the effectiveness of this technology.A = parameter A 5 = ductility B = parameter C = parameter d = axle body diameter D = wheel seat diameter f = loading frequency f i = frequency HV30 = hardness i = test level M = bending moment q = notch sensitivity parameter R = aspect ratio R e = yield strength R fL = fatigue limit for the smooth specimen R fE = fatigue limit for notched specimen R m = tensile strength R 0 = the lowest level of stress ŝ = standard deviation W o = modulus of resistance of the test specimen section δ = difference in stress between neighbouring test levels Δ = parameter depending on A, B, C ε_ = strain rate I N T R O D U C T I O NDemands for higher reliability and safety of railway vehicles have brought intensive research of degradation processes in railway wheelsets 1-3 and new approaches to wheelset design. 4 Extremely high repeated contact stresses between wheels and rails cause rolling contact fatigue. 1,2 A very serious form of damage to wheel seats is fretting fatigue, caused by small-amplitude oscillatory movement of wheels in press-fitted seat/axle joints. 3

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Section: Testing Materials and Experimental Proceduressupporting

confidence: 88%

Section: Testing Materials and Experimental Proceduresmentioning

confidence: 99%

Section: Materials For Axle Manufacture and Its Mechanical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fatigue limit of induction hardened railway axles

Fajkoš

Zima

Strnadel

2015

Fatigue Fract Eng Mat Struct

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Numerical parameter sensitivity analysis of residual stresses induced by deep rolling for a 34CrNiMo6 steel railway axle

Pertoll,

Buzzi,

Leitner

et al. 2024

Int J Adv Manuf Technol

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To optimise the benefits of the deep-rolling process in the service life context of treated components, the process application must be investigated. In addition to the reduction in surface roughness and near-surface material strengthening, compressive residual stresses are introduced, which are primarily responsible for the increase in service life for components, especially in the case of high-strength steel materials. A numerical parameter sensitivity analysis is performed in order to investigate the introduced residual stresses in detail. For this purpose, a validated deep-rolling simulation model is used, which replicates the deep rolling of a railway axle made of the high-strength steel material 34CrNiMo6. The model is based on an elastic-plastic Chaboche material model parameterised on uniaxial tensile and LCF test results and validated with residual stress measurements. Using this model as a basis, the effect of the main process parameters deep-rolling force, feed rate, friction coefficient, number of overruns, tool geometry, and shaft geometry on the resulting residual stress state are investigated. The results reveal that the deep-rolling force has the most significant influence on the introduced residual stress state and should therefore be highlighted. In the case of applying a deep-rolling force of more than 10 kN, maximum compressive residual stresses of around − 1000 MPa are introduced, and a strong saturating behaviour is shown. Maximum compensating tensile residual stresses of + 100 MPa occur below the surface. The main influence of the deep-rolling force is the effective depth achieved, which is determined by the depth of the zero crossing. This varies from 1 mm with an applied force of 2 kN to more than 3.5 mm with 20 kN. Furthermore, the results are analysed to conclude suggestions for the process’s applicability, and a proposal for an optimised deep-rolling treatment is presented. There multiple deep rolling with decreased deep-rolling forces is used to achieve a comparably optimised residual stress state. In summary, with the presented results, a contribution to a deeper understanding of the deep-rolling process can be achieved; the influence of the most important process parameters on the residual stress in-depth profiles is established; an optimisation proposal is presented; and correlations are found. Thus, the base work for further fatigue strength assessments and the optimisation of the deep-rolling process regarding the increase of service is laid.

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Fatigue Crack Growth in a Solid Circular Shaft Under Fully Reversed Rotating Bending

Torabi

Khavas

2012

J Fail. Anal. and Preven.

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An effect of strength of railway axle steels on fatigue resistance under press fit

Cited by 45 publications

References 8 publications

Fatigue limit of induction hardened railway axles

Fatigue limit of induction hardened railway axles

Numerical parameter sensitivity analysis of residual stresses induced by deep rolling for a 34CrNiMo6 steel railway axle

Fatigue Crack Growth in a Solid Circular Shaft Under Fully Reversed Rotating Bending

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