FATIGUE RESISTANCE OF A MEDIUM CARBON STEEL WITH A WEAR RESISTANT THERMAL SPRAY COATING |
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| Authors: | A. A. Rakitsky E. R. de los Rios K. J. Miller |
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| Affiliation: | Institute for Machine Reliability, Academy of Sciences of Belarus, 12 F. Scoryna Street, Minsk 220072, Republic of Belarus;SIRIUS, University of Sheffield, Mappin Street Sheffield S1 3JD, England |
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| Abstract: | Abstract— The fatigue behaviour of a Ni-Cr-base powder flame-spray coating on a 0.4% C steel is investigated. Fatigue tests were carried out using mild hour-glass profile specimens. Cracks were detected and measured using plastic replicas and an image analysis system. Coated specimens showed a slightly lower fatigue endurance than plain specimens under torsion loading, while the opposite was observed for push-pull loading. Microcracks in coated specimens invariably form at pores.
Contrary to the usual case of stage I shear growth for a plain 0.4% C steel in tension or torsion loading, the coated specimens show initial crack growth from pores along directions perpendicular to the maximum tensile stress. The crucial behaviour of short cracks, and their growth rates, relative to the thickness of the coating, are discussed in some detail. |
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