STEEL WITH REDUCED HARDENABILITY FOR SCREW SPRINGS WITH DIAMETRE OF RODS 17-23 mm AND SPRING FABRICATED OUT OF IT Russian patent published in 2009 - IPC C22C38/42 B61G9/08 B61G11/04 F16F1/02 

FIELD: metallurgy.

SUBSTANCE: invention can be implemented for fabricating big-size high loaded springs subject to heavy loads, and for screw springs of rolling stock of railroad transport with diametre of rod 17-23. Steel contains carbon, silicon, manganese, aluminium, nitrogen, sulphur, phosphorus, chromium, nickel, copper and iron at the following ratio of components, wt %: carbon 0.55-0.63, silicon 0.10-0.35, manganese ≤0.20, aluminium 0.02-0.06, nitrogen 0.004-0.016, sulphur ≤0.025, phosphorus ≤0.020, chromium 0.10-0.20, nickel 0.15-0.20, copper 0.15-0.20, iron the rest. Point of austenite grain of steel is 11-13; structure of steel is fine-needled martensite of tempering on surface and sorbite in core after surface-volumetric quenching and tempering.

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

2 cl, 1 tbl, 1 ex