MANUFACTURING METHOD OF CORROSION-RESISTANT TUBING Russian patent published in 2012 - IPC C21D9/14 C22C38/26 E21B17/01 

FIELD: metallurgy.

SUBSTANCE: tubes are made from steel containing the following components, wt %: carbon not more than 0.16, silicon 0.30-0.50, manganese 0.50-0.70, chrome 3.00-6.00, molybdenum 0.40-1.00, vanadium 0.04-0.10, niobium 0.04-0.10, aluminium 0.02-0.05, rare-earth metals 0.005-0.015, iron and inevitable impurities - the rest; flattening of tube wall is performed at temperature of 1050-900°C; cooling in the air after flattening is performed up to temperature of 700-650°C and reduction or calibration of diameter is performed at that temperature.

EFFECT: formation of steel structure which provides the stability of its characteristics throughout the length of manufactured tube.

3 tbl, 2 dwg