RU2006131200A - TUBING OF LOW CARBON, MICROALLOYED STEEL - Google Patents

Claims (3)

1. The tubular billet of low carbon microalloy steel, characterized in that it is made of steel containing the following ratio of components, wt.%: carbon [C] 0.16-0.22 Manganese [Mn] 1.30-1.70 silicon [Si] 0.35-0.55 vanadium [V] 0.10-0.20 molybdenum [Mo] 0.06-0.08 nitrogen [S] 0.005-0.015 arsenic [As] 0.0001-0.03 tin [Sn] 0.0001-0.02 lead [Pb] 0.0001-0.01 zinc [Zn] 0.0001-0.005 sulfur [S] 0.005-0.035 iron and inevitable impurities rest, when the relations (As + Sn + Pb + 5 · Zn) ≤0.07; 0.54≤ (C + Mn / 6 + Mo + V) ≤0.76, hot-rolled and normalized, has a ferritic perlite structure, real grain size is 5-10 points, macrostructure is central porosity, point heterogeneity, segregation square no more than 2, 0 points, shrink segregation and segregation strips no more than 1 point, non-metallic inclusions - point sulphides, point oxides, line oxides, brittle silicates, plastic silicates, undeformed silicates no more than 2.5 points, average for each type of inclusion, mechanical properties after normalization - temporary The ultimate tensile strength is 550-780 N / mm ² , the yield strength is not less than 410 N / mm ² , the elongation is not less than 22%, the impact work KU (-20 ° С) is not less than 35 J. 2. The pipe billet according to claim 1, characterized in that the steel further comprises, as impurities, wt.%: Phosphorus no more than 0.035, chromium no more than 0.30, nickel no more than 0.30, copper no more than 0.30. 3. A pipe billet according to any one of claims 1 and 2, characterized in that when the sulfur content is ≤0.020%, it has mechanical properties - temporary tensile strength 580-750 N / mm ² , yield strength not less than 430 N / mm ² , relative elongation not less than 24%, impact work KU (-20 ° С) not less than 45 J.