Influence of the Temperature and Frequency of Loading on the Contact Fatigue of 20KhN3A and ShKh15 Steels under the Acti
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INFLUENCE OF THE TEMPERATURE AND FREQUENCY OF LOADING ON THE CONTACT FATIGUE OF 20KHN3A AND SHKH15 STEELS UNDER THE ACTION OF CORROSIVE MEDIA B. P. Chaikovs'kyi,1 V. І. Kyryliv,2,3 V. R. Dutka,1 B. R. Tsizh,1 О. V. Maksymiv,3 B. М. Mykychak,1 and P. Ya. Sydor3
UDC 622.245.002.4.
We study the influence of temperature of a working medium and loading frequency on the contact fatigue of 20KhN3A and ShKh15 steels in oil and in a 3% NaCl aqueous solution. It is shown that, as the loading frequency increases, the contact fatigue of steels increases in a 3% NaCl aqueous solution but does not change in oil. At the same time, as temperature increases, the contact fatigue decreases in a 3% NaCl aqueous solution but remains almost constant in oil. It is shown that the outlined behaviors of the analyzed steels is explained by the action of the components of working media and their concentrations in the surface layers in the course of the tests. Keywords: contact fatigue, 20KhN3А and ShKh15 steels, temperature, loading frequency, working media.
Introduction Contact-fatigue resistance is an important operating characteristic of numerous components of machines and mechanisms (rolling bearings, drill bits, rolls of the rolling mills, gearings, etc.). For the production of these components, it is customary to use 20KhN3A steel after carburizing, quenching, and low tempering (components of drill bits) and ShKh15 steel after hardening and low tempering (races of rolling bearings). They operate under loads with different frequencies, as well as under the action of corrosive media [1, 2] and elevated temperatures. Under these conditions and in the presence of high contact loads, one may observe the phenomenon of saturation of the surface with components of the working media (in particular, with hydrogen, oxygen, and carbon) decomposed as a result of their thermal and mechanical destruction. These components saturate the surface layer as a result of mass transfer under the conditions of rapid plastic deformation [3] and affect its contact fatigue resistance. Under the indicated conditions, these elements are manly located on the grain boundaries and affect the resistance of the material to working loads in different ways. The aim of the present work is to investigate the influence of the frequency of loading and temperature on the contact fatigue of 20KhN3A and ShKh15 steels subjected to the action of working media after preliminary hydrogenation. 1 2 3
Hzhyts’kyi Lviv National University of Veterinary Medicine and Biotechnologies, Lviv, Ukraine. Corresponding author; e-mail: [email protected].
Karpenko Physicomechanical Institute, National Academy of Sciences of Ukraine, Lviv, Ukraine.
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 55, No. 5, pp. 103–108, September–October, 2019. Original article submitted April 12, 2019. 724
1068-820X/20/5505–0724
© 2020
Springer Science+Business Media, LLC
INFLUENCE OF THE TEMPERATURE AND FREQUENCY OF LOADING ON THE CONTACT FATIGUE
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Fig. 1. Schematic diagram of the tests (
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