SECTION IRON HOT-ROLLED MADE OF SPRING STEEL Russian patent published in 2008 - IPC C21D8/06 C22C38/60 

FIELD: metallurgy.

SUBSTANCE: invention concerns the metallurgy field. Particularly it concerns manufacturing of bundled rolled or bar metal of gage from 12 to 34 mm for producing heavy-loaded springs for various purposes. For supporting of heightened level of consumer behavior rolled metal is obtained from steel which consists in mass % of: C-(0.58-0.63), Mn-(0.60-0.90), Si-(1.60-2.00), Cr-(0.2-0.4), S-(0.005-0.015), N-(0.005-0.010), As-(0.0001-0.03), Sn-(0.0001-0.02), Pb-(0.0001-0.01), Zn-(0.0001-0.005), iron and inevitable admixtures are the rest, in ratio: (As+Sn+Pb+5×Zn)≤0.07; 1.14≤ (C+Si/4+Mn/6+Cr/5) ≤1.35. Admixtures: phosphorus - not more than 0,020%; nickel - not more than 0.020%; copper not more than 0.15%. Rolled metal has ferrite-pearlite composition without graphite, martensite, bainite and widmanstatten pattern areas, where effective grain size is 6-12 points, decarbonisated layer depth is not more than 1.5% to the side, macrostructure is: center porosity, spot inhomogeneity, liquating square is not more than 3 points for every kind, undershrinked sweat is not more than 3 points, liquating strip is not more than 1 point. Nonmetallic: spot sulphides, spot oxide, stitch oxide, fragile silicate, plastic silicate, unstrained silicate - not more than 2.5 points, tensile strength is not more than 850 N/mm², yield strength is not less than 500 N/mm², solidity is 192-269 HB, modulus of elongation is not less than 200000 N/mm², shear modulus is not less than 80000 N/mm².

EFFECT: rolled metal possesses favourable ratio of strength, plasticity and viscosity, mechanical anisotropy floor.

2 cl, 1 ex