STEEL FOR SCREW SPRINGS WITH DIAMETRE OF ROD 27-33 mm AND SPRING FABRICATED OUT OF THIS STEEL Russian patent published in 2009 - IPC C22C38/42 B61G9/08 B61G11/04 F16F1/02 

FIELD: metallurgy.

SUBSTANCE: invention can be implemented for fabrication of big size heavy loaded springs subject to high loads, particularly to fabrication of screw springs of rolling stock of railroad transport with diametre of rod 27-33 mm. Steel contains carbon, silicon, manganese, aluminium, nitrogen, sulphur, phosphorus, chromium, nickel, copper and iron at the following ratio of components, wt %: carbon 0.55-0.60, silicon 0.40-0.75, manganese 0.25-0.35, aluminium 0.02-0.06, nitrogen 0.004-0.016, sulphur ≤0.025, phosphorus ≤0.020, chromium 0.15-0.20, nickel 0.15-0.20, copper 0.15-0.20, iron the rest. Point of austenite grain of steel is 11-12 and structure is fine-needled martensite of tempering on surface and sorbite in core after surface-volumetric quenching and tempering.

EFFECT: upgraded level of operational characteristics, particularly mechanical properties, relaxation resistance, cyclic durability and corrosion resistance.

2 cl, 1 tbl, 1 ex