NITRO-CARBONISED STEEL PART WITH INDUCTION QUENCHING OF RAISED FATIGUE STRENGTH OF SURFACE AT HIGH TEMPERATURE AND PROCEDURE FOR ITS MANUFACTURE Russian patent published in 2011 - IPC C22C38/60 C22C38/14 C22C38/06 C21D1/06 C21D9/00 C21D9/32 C21D9/40 

FIELD: metallurgy.

SUBSTANCE: there is used steel containing, wt %: C: 0.005 - 0.8, Si: 2.0 and less, Mn: 0.2 - 3.0, P: 0.03 and less, S: 0.005 - 0.10, Ni: 3.0 and less including 0, Cr: 5.0 and less, including 0, Mo: 2.0 and less, including 0, W: 1.0 and less, including 0, B: 0.0050 and less, including 0, O: 0.0050 and less and N: 0.003 - 0.03 and additionally containing one or both Al: 0.005 - 0.2 and Ti: 0.005 - 0.2 and one or both V: 0.3 and less, including 0, and Nb: 0.3 and less including 0, iron and unavoidable impurities - the rest. Steel is subjected to nitro-carbonisation, successive quenching in oil or salt, successive induction heating and quenching with water or polymer quenching substance at temperature less, than 40°C. There is manufactured a part with concentration of N on the surface 0.1-0.8 wt % with concentration of N and C 1.0 - 2.0 wt %, amount of residual austenite on surface less, than 15 vol. %, depth of not complete quenched layer from surface less, than 5 mcm and semi-width of diffraction of roentgen beams on surface 6.0 degrees and more.

EFFECT: manufactured parts possess high fatigue strength of surface which results in increased output power of components of power transmissions of cars at reduced cost.

6 cl, 1 dwg, 2 tbl, 1 ex