ANNEALING METHOD IN BELL FURNACE Russian patent published in 2012 - IPC C21D9/48 C21D9/663 

FIELD: metallurgy.

SUBSTANCE: piles of rolls with temperature of 190-210°C are subjected at speed of 25-80°C/h to annealing beginning temperature of 610-670°C, exposure for 7-36 hours is performed at temperature decrease to annealing end temperature of 580-640°C; at that, annealing beginning temperature is higher than annealing end temperature by 20-40°C; then, at temperature of not more than 550°C there performed is accelerated cooling under muffle with its blowing with cold protective gas; unpacking is performed at temperature of not more than 120°C with further cooling in the air; after the annealing exposure is completed and heating is switched off, cooling under heating cap is carried out for not more than 13 hours.

EFFECT: reducing power consumption and obtaining the required set of mechanical properties with increased strength class of 260 to 420 heating.

2 cl, 1 ex, 2 tbl