RU2006145121A - TUBE BILLING FROM LOW-ALLOY STEEL - Google Patents

Claims (2)

1. The pipe billet of low alloy steel, continuously cast, hot rolled, having predetermined parameters of non-metallic inclusions, structure, actual grain size and mechanical properties, characterized in that the steel contains the following ratio of components, wt.%: carbon 0.16-0.24 manganese 1.10-1.60 silicon 0.12-0.17 chromium 0.005-0.30 vanadium 0.08-0.14 aluminum 0.02-0.04 copper 0.005-0.30 nickel 0.005-0.30 nitrogen 0.005-0.015 iron and inevitable impurities rest the tube billet has a ferritoperlite structure, the actual grain size is 5-8 points, according to the macrostructure: central porosity, point heterogeneity, segregation square, shrink segregation not more than 2 points for each species, segregation strips not more than 1 point, for non-metallic inclusions: sulfides, point oxides, line oxides, brittle silicates, plastic silicates, non-deforming silicates no more than 4.5 points for each type of inclusions, mechanical properties after normalization: temporary tensile strength n less than 450 N / mm ² , yield strength not less than 350 N / mm ² , elongation not less than 18%, impact strength at room temperature KCU not less than 30 J / cm ² . 2. The pipe billet according to claim 1, characterized in that, as unavoidable impurities, the steel additionally contains the following components, wt.%: Niobium not more than 0.020, titanium not more than 0.030, molybdenum not more than 0.10, sulfur not more than 0.030, phosphorus no more than 0,030.