Fatigue Crack Surface Topography after Plasma Nitriding Process

Abstract:

Fatigue characteristics of steel 41CrAlMo7-10 and topography analysis testing methodology of fish eye were studied. Both sets of samples were heat-treated at the same conditions and subsequently were plasma nitrided. The mixture ratio of these main gases, forming the atmosphere during the plasma nitriding was inverted for both sets of samples. Process parameters such as the duration, the applied voltage and the pulse length were identical for all samples. Following test after heat treatment and surface layer formation by plasma nitriding process for both sets of samples was the rotating bending fatigue testing in the machine R.R.Moore L2568 of Instron Co. The fatigue tests were carried out in accordance with the CSN 42 0363 Fatigue Testing of Metals, Methodology of Testing. Then, tests were evaluated numerically and graphically using Wöhler`s (S-N) curve in a semi-logarithmic form. The testing was stopped after reach the fracture of tested sample or after 10⁷ cycles. The surface topography of fatigue cracks were evaluated on Talysurf CCI. The topography analysis was mainly focused on the initial part of fatigue crack called the fish-eye. The topography analysis was performed only on one selected sample of each series.

• Periodical: Solid State Phenomena (Volume 258)
• Pages: 298-301
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.258.298
• Online since: December 2016
• Authors: Zbynek Studeny, Zdeněk Pokorný*, David Dobrocký
• Keywords: 41CrAlMo7-10 Steel, Crack Topography, Fatigue, Plasma Nitriding

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