METHOD FOR PRODUCTION OF HEAVY ROLLED PRODUCT FOR PRODUCTION OF PIPES OF MAIN PIPELINES Russian patent published in 2024 - IPC C21D8/02 C22C38/58 C22C38/54 C22C38/50 C22C38/48 C22C38/46 C22C38/44 C22C38/42 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production at reversing mill of heavy rolled tubular products for production of main pipelines. Method involves production of a continuously cast steel billet from steel with the following ratio of elements, wt.%: carbon 0.03–0.07, silicon 0.10–0.35, manganese 1.00–1.60, sulphur not more than 0.004, phosphorus not more than 0.015, chromium not more than 0.30, nickel not more than 0.30, copper not more than 0.30, aluminium 0.02–0.05, titanium 0.001–0.03, molybdenum not more than 0.30, vanadium not more than 0.10, niobium 0.02–0.08, nitrogen not more than 0.008, boron not more than 0.001, calcium 0.0005–0.006, iron and unavoidable impurities – the rest. Austenitization of the workpiece and the stage of roughing and finishing rolling are carried out to obtain finished heavy rolled products, wherein the stage of rough rolling is started at a temperature of not less than 980 °C and it is carried out for the thickness of the semi-finished product, which is not less than 4.5 thicknesses of the finished heavy rolled product, finishing rolling is started at temperature of 750–900 °C and finished at temperature of 710–860 °C. Finished heavy rolled product is accelerated cooled at rate of 10–35 °C/s from temperature 700–830 °C to temperature of 40–150 °C with final air cooling.

EFFECT: obtaining heavy rolled product of strength class up to K60, with operating temperature up to -60 °C and guarantee of resistance to carbon dioxide corrosion.

6 cl, 3 tbl