METHOD OF THERMAL TREATMENT OF COLD ROLLED BANDS OUT OF LOW CARBON STEEL Russian patent published in 2009 - IPC C21D9/663 C21D1/26 C21D9/48 

FIELD: metallurgy.

SUBSTANCE: cold rolled band of 3.0-3.5 mm thickness out of steel of 08U grade is heated for annealing in single-stack bell-type furnace with protective atmosphere; also there is carried out six-step heating of band at temperature 370°C, 500°C, 650°C, 710°C, 680°C and 630°C with specified conditioning at each step; while total time of heating is established out of dependence: T = 0.51(Q+40), where: T is time of heating, hour., Q - is weight of load, t. Protective atmosphere of the furnace consists of 93…96 vol. % of nitrogen and 4…7 vol.% of hydrogen.

EFFECT: improved mechanical properties of steel.

1 dwg, 1 ex