HARDENED MARTENSITIC STEEL WITH LOW OR ZERO CONTENT OF COBALT, METHOD OF PRODUCING PARTS OUT OF THIS STEEL AND PART PRODUCED BY THIS METHOD

摘要

FIELD: metallurgy.;SUBSTANCE: steel is produced that contains wt %: C 0.20-0.30, Co traces- 1, Cr 2-5, Al 1-2, Mo+W/2= 1-4, V traces-0.3, Nb traces-0.1, B traces - 30 parts per million, Ni 11-16, whereby Ni≥7+3,5 Al, Si traces - 1,0, Mn traces - 2,0, Ca traces - 20 parts per million, rare-earth elements traces - 100 parts per million, if N≤10 parts per million, then Ti+Zr/2 traces - 100 parts per million and Ti+Zr/2≤10 N, if 10 parts per million N≤20 parts per million, then Ti+Zr/2 traces - 150 parts per million, O traces - 50 parts per million, N traces - 20 parts per million, S traces - 20 parts per million, Cu traces -1, P traces - 200 parts per million, the rest is iron and unavoidable impurities getting into steel during melting. This steel is used for making a part by means of a method having the following stages: shaping processing, 600-675°C annealing for 4 to 20 hours followed by cooling in the air, heating to 900-1000°C for at least, 1 hour, followed by rapid cooling in oil or in the air, thus avoiding discharge of carbides at the austenite grain boundaries, hardening aging at 475-600°C, preferably at 490-525°C for 5-20 hours.;EFFECT: increased mechanical strength of the parts at high temperature.;28 cl, 2 tbl