METHOD OF PRODUCTION STRIPS FOR PIPES OF MAIN PIPELINES Russian patent published in 2010 - IPC C21D8/02 C22C38/12 C21D9/46 

FIELD: metallurgy.

SUBSTANCE: there is melted steel of following composition, wt %: carbon (0.04-0.08), manganese (1.65-2.05), silicon (0.16-0.40), nickel (0.02-1.00), copper (0.001-0.50), aluminium (0.02-0.05), molybdenum (0.001-050), niobium (0.04-0.07), vanadium (0.05-0.09) sulphur (0.001-0.003), phosphorus (0.003-012), titanium (0.010-0.020), iron - the rest; further, melt is continuously cast in slabs at temperature of austenisation A_r3+(480-550°C), and deformed at degree of 60-80 % first across lengthwise axis of slab, then in lengthwise direction relative to slab axis in interval of temperature 1020÷750°C; produced rolled product is cooled to temperature not over 250°C at average weight rate 35-70°C/sec. Further rolled product is heated to 570-670°C and cooled in air facilitating crack growth resistance ratio (P res) not more, than 0.25.

EFFECT: production of rolled material with upgraded indices of strength at simultaneous increased cold resistance and low temperature viscosity in zone of thermal effect during rolled product welding.

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