PROCEDURE FOR PRODUCTION OF THICK SHEET LOW ALLOYED STRIP Russian patent published in 2010 - IPC C21D8/02 C22C38/58 

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to rolling-mill production, and can be implemented at fabricating thick sheets and strips out of low alloyed steel. To increase strength characteristics and cold resistance at maintaining sufficient plasticity there is produced a work piece of steel containing, wt %: 0.04-0.07 C, 1.60-1.95 Mn, 0.15-0.35 Si, 0.2-0.3 Ni, 0.055-0.08 Nb, 0.04-0.3 Cr, 0.2-0.3 Mo, Cu<0.15, iron and additives with contents of each element of additive less 0.03 - the rest; also contents of manganese is bound with contents of carbon by dependence: Mn=(2.1-6·C)±0,07. Carbon equivalent is C_equiv=0.41-0.46. Further, there is performed austenization of the work piece at 1170-1200°C during not less, than 4 hours and rough rolling for thickness equal to 4.2-5.5 of finished strip thickness with temperature not less, than 870°C at finish rolling. A breakdown piece is cooled to 740-780°C before finish rolling whereupon it is subject to finish rolling at summary reduction ratio 75-85 % and accelerated cooling to 520-580°C. The work piece is rough rolled in a cross direction relative to its axis, while finish rolling is performed first in cross direction, then in lengthwise direction with summary reduction ratio in cross passes of finish rolling 5-20 %.

EFFECT: increased strength characteristics and cold resistance at maintaining sufficient plasticity of strip.

2 cl, 1 ex