ANNEALING METHOD OF LOW-CARBON SHEET STEEL Russian patent published in 2009 - IPC C21D9/48 C21D9/663 C21D1/26 

FIELD: metallurgy.

SUBSTANCE: heating of cold-rolled coils of thickness 0.42-0.49 m is implemented in bell-type furnace with protective atmosphere at defined heating rate up to defined temperature with isolation under the muffle and by cooling, at that in the capacity of protective atmosphere it is used 100% hydrogen, heating is implemented up to 670°C with the heating rate nomore than 90 degree/h up to achieving in came off by heating coil point of the temperature equal to 650°C, at the end of heating it is implemented gas purging up to increasing of protective atmosphere volume for 30% and isolation during 8-10 hours, at that it is implemented water cooling of furnace up to the temperature, defined from the formula: t =714 × h - 50°C, where h - strip thickness, mm. In the capacity of gas for purging it is used hydrogen.

EFFECT: increasing of the strip quality made of low-carbon steel.

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