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Hydrogen effect on the high-nickel surface steel properties during machining and wear with lubricants

Balitskii O. A., Kolesnikov V. O., Balitskii A. I., Eliasz J. J., Havrylyuk M. R.

Archives of Materials Science and Engineering

2020

Vol. 104, nr 2

49--57

Purpose: The aim of the proposed research is to investigate the hydrogen effect on the high-nickel steel surface properties changing during machining and wear with participation of lubricant-cooling environments. Design/methodology/approach: The approach of the fracture mechanics and physicalchemical methods surface properties investigation was used to formulate the conclusions. Applying of lubricant-cooling (liquid, solid, gaseous) technological environments (LCTE) has change the morphology of chips and roughness of contact 23Ni1Mo3Ti steel surfaces depending on the experimentally fixed hydrogen concentrations (4.62…12.0 ppm). It correlates with both the roughness of the treated surface and the nature of the cutting products fragmentation: the maximum concentration of hydrogen - in the chips coincides with the minimum size of its defragmentation and reduction of the surface roughness. For nitrogen and oxygen, a similar relationship is traced poorly. Findings: On the basis of the fracture mechanics approaches it is confirmed, that in the conditions of the application of hydrogen containing (as chemical composition) (up to 12 ppm) and hydrogen accumulated (in nano container) (up to 600 ppm) LCTE, hydrogen enters the near crack initiation contact zone before fracture and taking part in changing structural material fracture mechanisms, improves its mashinning processes. Research limitations/implications: The results obtained on laboratory specimens should be tested during machining of real details made from high-nickel steel. Practical implications: The created technological approaches can be used in practice evaluation of mechanical properties and residual of modern gas turbine parts. Originality/value: It was shown, that hydrogen containing (in chemical composition) and hydrogen accumulated (in nano container) LCTE permits the hydrogen to enter in the near crack initiation contact zone before fracture and taking part in changing structural material fracture mechanisms.

Wear resistance of hydrogenated high nitrogen steel at dry and solid state lubricants assistant friction

Balitskii O. A., Kolesnikov V. O., Balitskii A. I.

Archives of Materials Science and Engineering

2019

Vol. 98, nr 2

57--67

Purpose: This paper is devoted the investigation hydrogen influence on of wear resistance of high nitrogen steel (HNS) at dry and solid state lubricants assistant friction. It has been established that after hydrogenation at 250 N loading the wear rate increased by 2.9 ... 4.1 times. Microhardness of hydrogenated layer was 7.6 ... 8.2 GPa, that is increased after hydrogenation in two times. After adding the (GaSe)xIn1-x compounds to the tribo conjugates by X-ray diffraction analysis it has been established the appearance of new phases which formed during the friction process and detected on the friction surface. Design/methodology/approach: This work presents research results concerning the comparative tests of high nitrogen steels in the circumstances of dry rolling friction. It was conducted the experiments to determine the tribological properties of high-nitrogen steels under rolling friction. The test pieces were manufactured in the form of rollers, and rotated with a linear velocity 2.27 m/s (upper roller), 3.08 m/s (bottom roller). Upper roller is made from HNS was subjected for hydrogenation. Analysis of friction surfaces indicates the complex mechanism of fracture surfaces. The results of the local X-ray analysis and X-ray diffraction analysis has been established the appearance of new phases and elements on the friction surface. Findings: It has been found that the level of wear resistance of the investigated materials under hydrogenation. Compounds realize chemisorption, tribochemical mechanisms of the formation of thin protective (anti-wear, antifriction) layers on metal surfaces. Research limitations/implications: An essential problem is the verification of the results obtained using the standard mechanical tests, computer-based image analysis and other methods. Practical implications: The observed phenomena can be regarded as the basic explanation of reduces the plasticity characteristics after hydrogenation. Applying the (GaSe)xIn1-x compounds as a lubricant will allow the formation of films on friction surfaces that can minimize surface wear, which will contribute to the transition to a wear-free friction mode. The protective film is a barrier to high shear and normal loads, preserving the base metal of the part and providing reduced wear and friction. Originality/value: The value of this work is that conducted experiments permit to determine the tribological properties of high nitrogen steels under rolling friction after hydrogenation. After adding (GaSe)xIn1-x compounds to the tribo conjugates after due to X-ray diffraction analysis it has been established the appearance of new phases which formed during the friction process and detected on the friction surface.