Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100, Part III: Metallurgical Examination

Forster, Nelson H.; Rosado, Lewis; Ogden, W.; Trivedi, Hitesh K.

doi:10.1080/10402000903226317

Cited by 68 publications

(37 citation statements)

References 5 publications

(6 reference statements)

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“…9 The persistent carbides in these secondary hardening steels are used to explain the accumulation of plastic strain in affected regions that are not localised. 59 Butterflies are known to form at high contact stresses even in the M50/M50NiL alloys, 21 but have not been reported in any study from bearings that have experienced service. 60 Indeed, rolling contact fatigue is not a key feature in the failure of aeroengine bearings: the vast majority of operational failures in M50/M50NiL bearings are due to surface distress; [61][62][63] although such distress can initiate cracks that grow by a fatigue mechanism, leading eventually to spalling, the important Bhadeshia and Solano-Alvarez Elimination of white etching matter in bearing steels Materials Science and Technology 2015 VOL 31 NO 9 distinction is that initiation does not begin below the surface where rolling contact stresses are maximal.…”

Section: Hypothesis and Solutionsmentioning

confidence: 99%

“…16 These bands in 52100 steel are denuded in carbon and hence are soft relative to the matrix; 9,17 -20 the same is true of similar bands found in M50 bearings. 21 These softened bands are not associated with cracks or failure and hence are not discussed further. Other forms of white matter resulting from machining or other fabrication operations 22 are not relevant to the present discussion.…”

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Critical Assessment 13: Elimination of white etching matter in bearing steels

Bhadeshia

Solano-Alvarez

2015

Materials Science and Technology

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One form of damage due to rolling contact fatigue is the formation of localised regions of extremely hard material forming within the body of a bearing. These regions have a relatively homogeneous structure and hence etch mildly with respect to the surrounding unaffected matrix. They, therefore, appear white in a darker background when examined using optical microscopy. We assess here the cause of this damage and propose solutions that are backed by evidence that already is available. The issue is important because of the spate of unexpected failures in large wind turbine bearings and of generic importance in determining the life of more well behaved bearing applications.

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Section: Hypothesis and Solutionsmentioning

confidence: 99%

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confidence: 99%

Critical Assessment 13: Elimination of white etching matter in bearing steels

Bhadeshia

Solano-Alvarez

2015

Materials Science and Technology

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“…The improved performance of Pyrowear 675 and CSS 42L over M50 is largely attributed to the higher alloy content and relative hardness (yield strength) of the materials. As described by Forster [17], higher alloy content generally provides a material that resists micro-structural damage, improving fatigue life. Cronidur 30 as described by Tojhan [9], is an exception.…”

Section: Discussionmentioning

confidence: 97%

Rolling Contact Fatigue Evaluation of Advanced Bearing Steels with and Without the Oil Anti-Wear Additive Tricresyl Phosphate

2010

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The effect of the oil anti-wear additive tricresyl phosphate (TCP) on rolling contact fatigue (RCF) life of advanced bearing steels-AISI VIMVAR M50, CSS 42L, Pyrowear 675, and Cronidur 30 was investigated with silicon nitride balls at 177°C and at a maximum Hertzian stress of 5.5 GPa. TCP at 1% additive concentration was blended into a synthetic polyol ester turbine engine lubricant basestock having a nominal viscosity of 3 cSt at 100°C. Additionally, the basestock was fortified with the antioxidants dioctyl-diphenyl amine (DODPA) and phenyla-napthyl amine (PANA) at 1% concentration each. The presence of TCP has a measurable positive effect on RCF life and wear. Also, all the advanced bearing materials exhibited superior fatigue life compared to conventional bearing steel M50, both with and without TCP. The study indicates that current gas turbine lubricant formulations with TCP have positive effects on fatigue life and wear performance of M50, Pyrowear 675, CSS 42L, and Cronidur 30.

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“…Since the effective area over which load is supported rapidly increases with depth below a rolling surface, the high compressive stress occurring at the surface does not permeate the entire rolling member. RCF is responsible for the failure of rolling element bearings and may be defined as cracking or pitting limited to the near-surface layer of bodies in rolling/sliding contact [15].…”

Section: Rcf Performance Of Rolling Bearingsmentioning

confidence: 99%

Rework solution method on large size radial roller bearings

Chen

Xia

Qiu

2015

J Braz. Soc. Mech. Sci. Eng.

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L we Effective roller contact length, in millimeter z Principal direction distance, in millimeter ∑ρ Curvature sum, in millimeter X Tangential (over-rolling) direction Y Axial (lateral) direction Z Radial (depth) direction τ Shear stress, in newtons per square millimeter k 1 Variable related to the specific shearing stress Q max Maximum Hertz stress, in newtons per square millimeter τ x (Real) stress refers to X direction, in newtons per square millimeter τ y (Real) stress refers to Y direction, in newtons per square millimeter τ z (real) stress refers to Z direction, in newtons per square millimeter τ 45 Maximum shear stress, in newtons per square millimeter τ max Maximum shear stress, in newtons per square millimeter σ e v.Mises Resulting v. Mises equivalent stress, in newtons per square millimeter z Depth along Z axis at x = 0, y = 0, in millimeter z max Depth to maximum shear stress at x = 0, y = 0, in millimeter k 2 Variable related to the maximum shearing stresses V Stressed volume, m 3 , (in. 3 ) Vz Stressed volume removed by honing or grinding, m 3 , (in. 3 ) V 1 -z Remaining stressed volume after honing or grinding, m 3 , (in. 3 ) L t Race track length, in millimeter D e Raceway diameter of out ring, in millimeter d i Raceway diameter of out ring, in millimeterAbstract The aim of this paper is to propose and verify a new rework solution method on large size radial roller bearing. Bearing rework is developing rapidly owing to cost control and greenhouse effect. General rework procedures and rules are evaluated by relative files and executed by most famous bearing suppliers. All defective rolling elements are scrapped according to the existing rework solutions, which leads to tremendous wastage. We draw our attention to the possibility of reusing large size rollers. In the procedure, rolling contact fatigue characteristic of roller bearings is analyzed and the solution method by reusing large size rollers is obtained in the paper. In view of greatly changing the rollers, rolling bearing design method is involved in the new solution method. This is significantly different from the old methods. In addition, the rating life of reworked bearing is re-calculated for reliability.Keywords Radial roller bearing · Rolling contact fatigue · Rework solution · Reworked bearing life List of symbols σ max Maximum stress, used in fatigue criterion, in newtons per square millimeter σ (Real) stress, used in fatigue criterion, in newtons per square millimeter P r Dynamic equivalent radial load, in newtons bSemi-minor axis of the projected contact ellipse, in millimeter

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Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100, Part III: Metallurgical Examination

Cited by 68 publications

References 5 publications

Critical Assessment 13: Elimination of white etching matter in bearing steels

Critical Assessment 13: Elimination of white etching matter in bearing steels

Rolling Contact Fatigue Evaluation of Advanced Bearing Steels with and Without the Oil Anti-Wear Additive Tricresyl Phosphate

Rework solution method on large size radial roller bearings

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