BAND OUT OF MEDIUM CARBON BORON CONTAINING STEEL OF UPGRADED HARDENABILITY AND CUTABILITY Russian patent published in 2008 - IPC C21D8/02 C22C38/60 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: band of 32×90 mm is produced out of steel containing wt %: C 0.34-0.38, Mn 1.00-1.30, Si 0.15-0.35, Cr 0.05-0.20, Nb 0.005-0.020, S 0.020-0.040, Al 0.020-0.050, Ti 0.020-0.04, Ca 0.001-0.010, N 0.005-0.010, B 0.001-0.005, As 0.0001-0.03, Sn 0.0001-0.02, Pb 0.0001-0.01, Zn 0.0001-0.005, iron and impurities at ratio (As+Sn+Pb+5×Zn)≤0.07, Ca/S≥0.065, (Ti/48+Al/27)-N/14≥0.6×10^-3. Band is produced hot rolled, it has ferrite-pearlite structure, dimension of actual grain is 5-9 points, depth of decarbonized layer is not more than 0.7 mm, non-metallic inclusions of pointed sulphides, pointed oxides, stripped oxides, fragile silicates, plastic silicates, non-deforming silicates are with average point of not more than 3.0 in each kind, macrostructure on central porosity, pointed non-uniformity, liquation square, sub-shrinking liquation is not more than 1 point, σt is not more than 640 MPa, δ is not less than 16%, ψ is not less than 50%, hardenability on hardness of sample at end tempering at distance from end of 1.5 mm is not more than 51-58 HRC, at distance from end of 9 mm is not more than 46 HRC, at distance from end of 15 mm is not more than 42 HRC. Cutability on cutter back facet wear value h₃ is not more than 0.35 mm at cut path L=1320m.

EFFECT: upgraded hardenability, wear resistance and cutability at optimal viscosity and plasticity.

2 cl, 1 ex