RU2006131196A - TUBE BILLING FROM LOW-ALLOY STEEL - Google Patents

Claims (4)

1. The pipe billet of low alloy steel having predetermined parameters of the structure, mechanical properties, characterized in that the billet is made of steel containing the following ratio of components, wt.%: carbon [C] 0.10-0.20 Manganese [Mn] 1.0-1.35 silicon [Si] 0.15-0.40 vanadium [V] 0.025-0.080 nitrogen [N] 0.005-0.009 arsenic [As] 0.0001-0.03 tin [Sn] 0.0001-0.02 lead [Pb] 0.0001-0.01 zinc [Zn] 0.0001-0.005 iron and inevitable impurities rest, when the relations (As + Sn + Pb + 5 · Zn) ≤0.07; [C + (Mn / 6) + (V / 5)] ≤0.42, hot-rolled, normalized, has a ferritic perlite structure, actual grain size is 5-10 points, macrostructure is central porosity, point heterogeneity, segregation square, shrink liquation no more 2.0 points, segregation strips no more than 1 point, non-metallic inclusions - point sulphides, point oxides, line oxides, brittle silicates, plastic silicates, undeformed silicates not more than 3.0 points, average for each type of inclusions, mechanical properties in a normal state - VR mennoe Tensile strength 400-585 N / mm ^2, yield stress of not less than 220 N / mm ^2, the relative elongation of at least 30%, impact strength KCV (+ 20 ° C) not less than 39.2 J / cm ^2. 2. The pipe billet according to claim 1, characterized in that the steel further comprises, as impurities, wt.%: Phosphorus not more than 0.025, sulfur not more than 0.010, chromium not more than 0.20, copper not more than 0.15, molybdenum not more than 0.07. 3. The pipe billet according to any one of claims 1 and 2, characterized in that when the content in steel C (0.10-0.15)%, the billet has mechanical properties in a normalized state - temporary tensile strength 400-560 N / mm2, yield strength of at least 220 N / mm ² , elongation of at least 32%, impact strength KCV (+ 20 ° C) of at least 44.2 J / cm ² . 4. The pipe billet according to any one of claims 1 and 2, characterized in that at a content of C (0.15-0.20)%; the workpiece has mechanical properties in a normalized state - temporary tensile strength 415-585 N / mm ² , yield strength not less than 241 N / mm ² , elongation not less than 30%, impact strength KCV (+ 20 ° С) not less than 44,2 J / cm ² .