ROUND ROLLED BARS OF ALLOY SPRING STEEL Russian patent published in 2007 - IPC C21D8/06 C22C38/60 

FIELD: metallurgy, namely production of rolled round bars of spring steel for making springs for important designation.

SUBSTANCE: rolled bars are produced from steel containing next relation of ingredients, mass.%: carbon, 0.53 - 0.58; manganese, 0.60 - 0.80; silicon, 1.40 - 1.60; chrome, 0.60 - 0.80; aluminum, 0.005 - 0.025; nitrogen, 0.005 - 0.008; arsenic, 0.0001 - 0.03; tin, 0.0001 - 0.002; lead, 0.0001 - 0.001; zinc, 0.0001 - 0.005; iron and inevitable impurities, the balance at relation As + Sn + Pb + 5 x Zn < 0.07. Content of impurities, mass.%: copper, no more than 0.08; vanadium, no more than 0.005; nickel, no more than 0.10; titanium, no more than 0.03; molybdenum, no more than 0.10; sulfur, no more than o.015; phosphorus, no more than 0.015; oxygen, no more than 0.002. Hot rolled piece has ferrite-pearlite microstructure without martensite, total depth of decarburized layer no more than 0.2 mm for side, temporary rupture resistance 900 - 1150 N/mm², percentage necking no less than 35%. As for non-metallic inclusions, rolled piece includes point sulfides, point oxides, line oxides, brittle silicates, plastic silicates, non - deformed silicates, no more than 2.5 marks for each type of inclusions.

EFFECT: high level of consumer's properties, desired relation of strength, ductility and viscosity values, minimum degree of properties anisotropy, rational winding condition.

2 cl, 1 ex