English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Purpose. Carburized chromium-nickel steels are widely used in the manufacture of drilling tools, gears, shafts, bushings and other parts which may be subjected to thermal effects and significant heating by friction at high speeds of sliding during operation. The aim of the paper is studying the possibilities of increasing the resistance of carburized chromium-nickel steel to thermal softening and heat seizure in the case of high-speed sliding friction by frictional treatment with sliding indenters. Methods. Steel 20KhN3A (wt. %: 0.20 C, 0.68 Cr, 2.90 Ni, 0.14 Mo) is subjected to carburizing, three heat treatments (quenching from 810 °C in oil; quenching and deep-freeze treatment at −196 °C; quenching and tempering at 180 °C) and frictional treatment using Al2O3 or hard-alloy VK8 indenters. The structure and phase composition of the steel are studied by transmission electron microscopy and X-ray analysis. The effect of tempering temperature in a vacuum at 100 °C to 700 °C on the microhardness of the carburized steel surface and the tribological properties (wear rate and friction coefficient) during unlubricated friction on the steel disk with sliding speeds of 1.5 and 4.5 m/s is determined. Results: Friction treatment leads to the formation of a nanostructured surface layer and increases the hardness of the carburized surfaces from 7.3‒9.5 to 10.1‒11.6 GPa. The presence of metastable retained austenite (25‒30 vol. %) in low-tempered steel provides a significant increase in the depth of hardening during friction treatment as a result of the deformation decay of austenite and its transformation into high-strength strain-induced martensite. Nanostructuring frictional treatment improves the resistance to softening of carburized steel with different initial structures during heating to temperatures of 500‒600 °C. Frictional treatment of quenched and lowtempered carburized steel enhances the heat wear resistance in tests with sliding friction at high speeds (over 2 m/s), when there is an intense in frictional heat, leading to the thermal softening of the surface. Nanostructuring frictional treatment provides not only a significant increase in wear resistance, but also a decrease in the friction coefficient at sliding speeds of 2.3‒3.0 m/s.

Improving the thermal stability and heat wear resistance of carburized chromium-nickel steel by nanostructuring frictional treatment