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

Abstract

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.