METHOD FOR PRODUCING OF CHROMIUM-NICKEL SHEET STEEL Russian patent published in 2007 - IPC C21D8/00 

FIELD: rolling and thermal processing in metallurgical industry.

SUBSTANCE: method involves heating flat blanks to austenite conditioning temperature; subjecting blanks to multiple-pass reversing hot rolling process with regulated reducing action in passes; finishing rolling process at predetermined final rolling stage temperature; holding sheets in air and quenching in water, with holding duration time and temperature at final rolling stage being set depending on content of chemical elements in steel according to ratios: T_fr≥850 C and ι≤30 s at 2·C+Ni+Cr=0.90-1.80; T_fr≥750 C and ι≤55 s at 2·C+Ni+Cr=1.81-3.40; T_fr≥700 C and ι≤65 s at 2·C+Ni+Cr=3.41-4.80, where T_fr is temperature at final rolling stage; ι is holding duration time before quenching process; C, Ni, Cr is content in steel of carbon, nickel and chromium, correspondingly, wt%. On rolling of sheets having thickness below 7 mm, relative reduction in each pass is kept within the range of 30-50%.

EFFECT: improved quality, stabilized mechanical properties, increased resistance to high-energy impact-pulsed loadings and increased yield of steel sheets.

2 cl, 2 tbl, 3 ex