RU2006146637A - PIPE BILLING FROM ALLOYED, HEAT-RESISTANT STEEL - Google Patents

Claims (2)

Tubular billet of alloyed, heat-resistant steel, having predetermined parameters of the structure and mechanical properties, characterized in that the billet is made of steel containing the following ratio of components, wt.%: carbon 0.22-0.28 manganese 0.50-0.70 silicon 0.17-0.37 chromium 0.80-1.10 nickel 0.005-0.25 molybdenum 0.15-0.25 vanadium 0.06-0.11 niobium 0.03-0.06 titanium 0.01-0.03 aluminum 0,020-0,05 copper 0.005-0.25 sulfur 0.005-0.013 nitrogen 0.005-0.008 calcium 0.001-0.005 arsenic 0.0001-0.03 tin 0.0001-0.02 lead 0.0001-0.01 zinc 0.0001-0.005 iron and inevitable impurities - the rest, when performing the following ratios: amount: (As + Sn + Pb + 5 × Zn) ≤0.05; [C + Mn / 6 + (Cr + Mo + V + Nb) / 5 + (Ni + Cu) / 15] ≤0.70; Ca / S≥0.1, continuously cast, hot-rolled, has a ferrite-pearlite structure, the actual grain size is 6–9 points, the macrostructure is central porosity, point heterogeneity, segregation square, shrink segregation is not more than 3 points for each type, segregation strips are not more than 2 points, non-metallic inclusions: sulfides , point oxides, line oxides, brittle silicates, plastic silicates, undeformed silicates not more than 4.0 points for each type of inclusions, mechanical properties after normalization - temporary resistance to fracture a yield of at least 685 N / mm ² , a yield strength of at least 490 N / mm ² , a relative elongation of at least 12%, a relative narrowing of at least 35%. 2. The pipe billet according to claim 1, characterized in that the steel further comprises, as impurities, wt.%: Phosphorus no more than 0.025 and hydrogen no more than 2 × 10 ^-6 (2ppm).