PIPE SHELL MADE OF LOW-ALLOY STEEL Russian patent published in 2009 - IPC C21D8/10 C22C38/60 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy field. Particularly it relates to manufacturing of pipe shell of diameter from 80 till 180 mm. For providing of higher level of consumer properties with favorable relation of strength, flexibility, viscosity and minimal level of mechanical anisotropy pipe shell is implemented of steel, containing, wt %: carbon 0.17-0.22, manganese 1.30-1.60, silicon 0.35-0.55, aluminium 0.020-0.060, nitrogen 0.005-0.015, arsenic 0.0001-0.03, tin 0.0001-0.02, lead 0.0001-0.01, zinc 6.0001-0.005, iron and unavoidable admixtures, with implementation of components ratio: As+Sn+Pb+5×Zn≤0.07; C+Mn/6≤0.48. In the capacity of admixtures steel contains, wt %: niobium non more than 0.02, phosphorus non more than 0.030, chrome non more than 0.30, nickel non more than 0.30, copper non more than 0.30, molybdenum non more than 0.05, vanadium non more than 0.02%, titanium non more than 0.01, sulphur non more than 0.030. Additionally it allows lamellar ferrite-perlitic structure, size of effective grains is 6-9 points, macrostructure by center porosity, dotted nonuniformity, segregate square, undershrinked segregation non more than 2 points per each kind, segregate strips non more than 1 points, nonmetallics by sulphides, dotted oxides, stitch oxides, fragile silicates, flexible silicates, non-strained silicates non more than 4.0 points per each kind of inclusions, tensile strength is non less than 400 N/mm², yield strength no less than 250 N/mm², percentage elongation non less than 22%.

EFFECT: providing of increased level of consumer properties at favorable correlation of strength, flexibility, viscosity and minimal length of mechanical anisotropy.

2 cl, 1 ex