RU2006146638A - PIPE PROCESSING FROM MID-CARBON MICROALLOYED STEEL - Google Patents

Claims (2)

A pipe billet of medium carbon microalloyed steel made of 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 0.40-0.50 manganese 0.80-1.40 silicon 0.17-0.37 chromium 0.005-0.25 niobium 0,040-0,11 molybdenum 0.001-0.12 iron and inevitable impurities rest, the billet has a ferrite-pearlite structure, the actual grain size is 5-8 points, according to the macrostructure: central porosity, point heterogeneity, shrinkable segregation, segregation square no more than 2 points for each type, segregation strips - not more than 1 point, for 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 tensile strength not less than 500 N / mm ² , yield strength not less than 390 N / mm ² , elongation not less than 20%. 2. The pipe billet according to claim 1, characterized in that the steel additionally contains the following components as inevitable impurities: niobium not more than 0.02%, arsenic not more than 0.03%, tin not more than 0.02%, lead no more 0.01%, zinc no more than 0.005%, nitrogen no more than 0.010%, copper no more than 0.25%, nickel no more than 0.25%, sulfur no more than 0.045%, phosphorus no more than 0.045%.