MANUFACTURING METHOD OF HOT-ROLLED PLATE FROM HIGH-STRENGTH COLD-RESISTANT STEEL Russian patent published in 2012 - IPC C21D8/02 

FIELD: metallurgy.

SUBSTANCE: steel includes the following components, wt %: C 0.02÷0.15, Mn - 1.20÷2.0, Si - 0.10÷0.50, Nb - 0.010÷0.10, Al - 0.01÷0.07, Ti - 0.005÷0.04, N - 0.003÷0.012, S - 0.0005÷0.010, P - 0.001÷0.015, Fe - the rest; continuous pouring on workpieces, heating of slabs, preliminary and final rolling and accelerated cooling; at that, after heating slabs are pre-rolled with total deformation of 50-70% in the direction perpendicular to slab axis. Then, final rolling is performed first in the direction perpendicular to the axis, and then along the roll axis with total deformation of 65-80% at temperature of 900-750°C; at that, 30-40% of total deformation falls on rolling in the direction perpendicular to roll axis; after that, accelerated cooling is performed from temperature Ar₃±20°C to temperature of 600-400°C, and then, slow cooling is performed to temperature of 20-200°C at speed of 0.05-0.15 deg/s. Steel also includes one or several elements of the group, wt %: Mo - 0.05÷0.35, V - 0.01÷0.15, Ni - 0.10÷0.50, Cu - 0.1÷0.50, Cr - 0.1÷0.50, Ca - 0.0002÷0.005.

EFFECT: increasing strength, cold resistance and low-temperature viscosity of rolled plate, excluding anisotropy of properties as to impact strength in longitudinal and transverse direction of the rolled plate.

2 cl, 1 ex, 3 tbl