R Gnanamoorthy

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.

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.

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.

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.