RAIL Russian patent published in 2018 - IPC C22C38/24 C22C38/46 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to high-strength rail used on freight railways. Rail is made of steel, containing, by mass %: C: from 0.75 to 0.85; Si: from 0.10 to 1.00; Mn: from 0.30 to 1.20; Cr: from 0.20 to 0.80; V: from 0.01 to 0.20; N: from 0.0040 to 0.0200 and a residue of Fe and impurities. Steel may further comprise at least one element of, by weight: Mo: from 0 to 0.50; Co: from 0 to 1.00; B: from 0 to 0.0050; Cu: from 0 to 1.00; Ni: from 0 to 1.00; Nb: from 0 to 0.0500; Ti: from 0 to 0.0500; Mg: from 0 to 0.0200; Ca: from 0 to 0.0200; REM: from 0 to 0.0500; Zr: from 0 to 0.0200; Al: from 0 to 1.00; P ≤ 0.0250 and S ≤ 0.0250. Structure of the rail to a depth of 25 mm from the outer surface of the head part includes 95 % or more of perlite and has a hardness in the range of HV 350–480. Particles of carbonitrides V having an average grain size of 5–20 nm are present at 1.0 mcm² cross-sectional area in the position at a depth of 25 mm from the outer surface of the head part in an amount of 50 to 500. Value obtained by subtracting the hardness at a position at a depth of 25 mm from the outer surface of the head part from hardness at a position at a depth of 2 mm from the outer surface of the head part is from HV 0 to HV 40. Following component ratios are to be maintained: 1.00<Mn/Cr≤4.00 and 0.30≤0.25×(Mn+Cr)≤1.00.

EFFECT: high resistance to wear and resistance to internal fatigue damage are provided.

3 cl, 9 dwg, 11 tbl