TUBE STOCK OUT OF BALL BEARING STEEL Russian patent published in 2008 - IPC C21D8/10 C22C38/18 C22C38/60 

FIELD: metallurgy.

SUBSTANCE: invention refers to production of tube stock of 80-180 mm diameter. To facilitate upgraded level of consumer characteristics it is produced out of steel containing wt %: C 0.95-1.05, Mn 0.20-0.40, Si 0.17-0.37, Ni 0.005-0.30, Al 0.005-0.05, V 0.005-0.03, S 0.005-0.020, P 0.005-0.027, Cr 1.30-1.65, N 0.005-0.012, As 0.0001-0.03, Sn 0.0001-0.02, Pb 0.0001-0.01, Zn 0.0001-0.005. iron and unavoidable impurities - the rest at the ratio of: (As+Sn+Pb+5×Zn)≤0.07; 0.30≤(Mn/6+Cr/5)≤0.38, at that it has grain pearlite structure and dimension of actual grain 6-9 points, macrostructure - central porosity, pointed non-uniformity, and sub-shrinking liquation not more, than 2 points in each kind, liquation square and liquation strips not more, than 0.5 point, non-metallic inclusions: pointed sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non-deformed silicates not more than 2.0 points in each kind of inclusions, tensile strength not less, than 590 N/mm², yield point not less, than 390 N/mm², specific elongation not less, than 21%, contraction ratio not less, than 45%, impact resilience KCU not less, than 440 kJ/m², hardness 179-217 HB.

EFFECT: facilitating upgraded level of consumer characteristics.

4 cl, 2 ex