MANUFACTURING METHOD OF HOT-ROLLED PIPE STEEL Russian patent published in 2012 - IPC C21D8/02 C22C38/20 C22C38/48 

FIELD: metallurgy.

SUBSTANCE: manufacturing method involves steel making, out-of-furnace treatment, continuous pouring, austenisation of workpiece with heating up to 1180÷1240°C, preliminary deformation and final deformation with total reduction degree of 65÷80% and end temperature of plastic deformation at the interval of Ar₃+(20÷50)°C; at that, after completion of final deformation the accelerated water cooling of the strip is performed to 560÷620°C at cooling rate of 1÷4°C/s, rolling and further cooling of the roll in still air to the ambient temperature.

EFFECT: providing uniform mechanical properties throughout the length of the rolled steel in conditions of high-productivity wide-strip hot-rolling mill having low reducing ability of finishing group.

4 cl, 1 ex, 2 tbl