HIGH STRENGTH SPRING, METHOD FOR ITS MANUFACTURE, STEEL FOR HIGH STRENGTH SPRING AND METHOD FOR ITS MANUFACTURE Russian patent published in 2019 - IPC C22C38/48 C21D9/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, in particular to the manufacture of high-strength springs used, in particular, in the automotive industry. Spring is made of steel containing, wt.%: C: 0.40–0.50; Si: 1.00–3.00; Mn: 0.30–1.20; Ni: 0.05–0.50; Cr: 0.35–1.50; Mo: 0.03–0.50; Cu: 0.05–0.50; Al: 0.005–0.100; V: 0.05–0.50; Nb: 0.005–0.150; N: 0.0100–0.0200; P: 0.015 or less; S: 0.010 or less, the balance is Fe and unavoidable impurities. Steel is hardened at a temperature of 950 °C or more and 1,000 °C or less and tempering at a temperature of 250 °C or more and less than 390 °C. Compound V, which is at least one of carbide V and carbonitride V, is in solid solution in Fe at the quenching temperature, and thereafter the compound Nb is released and surrounds, which is at least one of Nb carbide, Nb nitride and Nb carbonitride.

EFFECT: manufactured springs have high resistance to hydrogen embrittlement, endurance in corrosive conditions and resistance to delayed fracture.

8 cl, 4 dwg, 1 tbl, 3 ex