Now showing 1 - 7 of 7
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    Development of a fretting wear test rig and preliminary studies for understanding the fretting wear properties of steels
    (01-01-2006)
    Ramesh, R.
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    Rolling element bearings experience fretting wear type of failures due to small relative oscillatory motion existing between races and rolling elements of the bearing. Small oscillatory motion between contacting surfaces that occur due to overall machine or system vibration and unexpected loads in service causes accumulation of wear debris in the contact zone and accelerate the wear process. A fretting wear test rig is designed and developed in the laboratory for understanding the fretting wear behavior of bearing materials. The test rig is designed for testing at slip amplitudes ranging from 20 to 200 μm and test frequencies ranging from 1 to 30 Hz. Preliminary studies for understanding the fretting wear characteristics were conducted on hardened and tempered bearing steel, En31 and widely employed hardened and tempered structural steel, En24 at various normal loads. Coefficient of friction during fretting tests was high during the initial stages of fretting tests and reached a steady state. The coefficient of friction depends on the normal load. Wear scar morphology reveals the nature of contact exhibited by the fretting contacts. © 2004 Elsevier Ltd. All rights reserved.
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    Effect of post oxidation on the fretting wear behavior of liquid nitrided En 24 steel
    (31-03-2006)
    Ramesh, R.
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    Fretting wear is a low amplitude reciprocating sliding wear that is observed in many machine elements. Effect of post oxidation on fretting wear behaviour of liquid nitrided structural steel, En 24, against the hardened and tempered En 31 steel was investigated. Oxidation treatment carried out at a temperature of 773 K leads to formation of stable oxide layer over the compound layer. The oxide layer mainly consists of magnetite (Fe3O4) and hematite (Fe2O3) phases. Fretting wear studies were carried out using cylindrical specimens at constant slip amplitude 60 μm and at different normal loads. The coefficient of friction against number of run was plotted. The effect of post oxidation duration on fretting wear behavior was reported in the form of fretting wear loss and friction coefficient. The thickness of oxide layer formed affects the friction and wear characteristics under fretting conditions. © 2005 Elsevier B.V. All rights reserved.
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    Fretting wear behavior of liquid nitrided structural steel, En24 and bearing steel, En31
    (10-01-2006)
    Ramesh, R.
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    Fretting wear failures are reported in many bearing-shaft assemblies. Fretting wear characteristics of structural steel, En24 in as-received, hardened-tempered and liquid nitrided condition, when fretted with hardened-tempered bearing steel, En31 is reported in this paper. Tests were conducted at different normal loads and at constant slip amplitude under unlubricated conditions. Coefficient of friction under fretting conditions and wear resistance were measured. Surface chemistry influences the fretting wear behavior more than the hardness of the material. The mono phase epsilon iron nitride structure of compound layer formed in liquid nitriding process offers improved fretting wear resistance against bearing steels. The fretting wear resistance also depends upon the normal load and the nature of contact, stick-slip or gross slip. © 2005 Elsevier B.V. All rights reserved.
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    Effect of hardness on fretting wear behaviour of structural steel, En 24, against bearing steel, En 31
    (01-01-2007)
    Ramesh, R.
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    Fretting wear damage is frequently reported in the races of rolling element bearings and leads to the increased noise and vibration in the total machinery. The fretting wear studies were conducted on the as-received and hardened and tempered En 24 steel fretted against hardened and tempered bearing steel, En 31. Tests were conducted at different normal loads under unlubricated dry conditions. The coefficient of friction depends on the contact conditions, whether it is gross slip or stick slip. Hardness has only marginal effect on improving the fretting wear resistance. © 2006.
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    Artificial neural network prediction of fretting wear behavior of structural steel, en 24 against bearing steel, en 31
    (01-12-2007)
    Ramesh, R.
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    In this study, artificial neural network (ANN) technique is used to predict the friction and wear behavior of various surface-treated structural steel (En 24) fretted against bearing steel (En 31). A three-layer neural network with a back propagation algorithm is used to train the network. Fretting wear volume and coefficient of friction obtained at different normal loads (ranging between 2.4 and 29.4 N) for various treated samples (hardened, thermo-chemically treated, MoS 2 coated) were used in the formation of training data of ANN. Results of the predictions of ANN are in good agreement with the experimental results. The degree of accuracy of predictions was 96.3 and 95.7% for fretting friction coefficient and wear, respectively. © 2007 ASM International.
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    Fretting wear behaviour of liquid nitrided En24 steel fretted with the hardened En31 bearing steel
    (01-12-2004)
    Ramesh, R.
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    Fretting is a form of surface damage encountered in the machine components which experience small oscillatory movements. Fretting failure was reported in the machine elements like bearing races, bolt and rivet joints, turbine blades, etc., The contact zone in the mating parts is prone for early crack nucleation due to the presence of wear debris, which are not totally removed due to small oscillatory motion. Fretting wear behaviour of the surface treated high strength structural steels is reported in this paper. Studies were conducted in the laboratory developed fretting wear test rig. Fretting wear behaviour of structural steel, En24, in the as received condition and liquid nitrided conditions was fretted with the hardened and tempered bearing steel, En31, which represents the typical bearing shaft contacts in many assemblies. The coefficient of friction and wear loss strongly depended upon the surface treatment and normal load. The coefficient of friction decreased with increasing normal load. The fretting contact conditions, stick-slip or gross slip, strongly depended on the material composition and influences the fretting behaviour. Copyright © 2004 by Society for Advancement of Heat Treatment & Surface Engineering (SAHTSE).
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    An investigation on fretting wear behaviour of MoS2-bonded coating on AISI 4340 steel
    (01-02-2007)
    Ramesh, R.
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    Fretting wear characteristics of Molybdenum disulphide (MoS2)-bonded solid lubricant coating on structural steel, AISI 4340, when fretted against hardened-tempered bearing steel, AISI 52100 are reported in this paper. Fretting wear tests were conducted at different normal loads and at constant slip amplitude of 60 μm. Coefficient of friction under fretting conditions and wear resistance were measured. The MoS2-bonded solid lubricant offers improved fretting wear resistance against bearing steels. Substrate hardness has influenced the coating behaviour at high loads. The fretting wear resistance also depends upon the normal load and the nature of contact, stick slip, or gross slip. © IMechE 2007.