| 摘要 |
PURPOSE:To prevent seizure by retarding the removal of an outer cover in such a way that the temp. difference from the outside coiling parts of tight coils attains specific temp. or below at the point of the time when the coolest point of the tight coils drops down to the recrystallization temp. of steel in the cooling process after heating to prescribed temp. for a prescribed time. CONSTITUTION:Cold rolled steel strips of low carbon steel are taken up in the form of tight coils and are put in a box type annealing furnace 1, and an inner cover 4 is placed on tight coils 3. Thereafter, a gaseous atmosphere is introduced into the cover 4 to purge the inside of the said cover, then burners 2 provided to an outer cover 5 are operated to anneal the tight coils. Thereafter, the coils are cooled, and in this cooling, the timing for removal of the cover 5 is retarded in such a way that the temp. difference from the outside coiled parts of the coils 3 attains <=50 deg.C at the point of the time when the coolest point of the tight coils 3 drops down to the recrystallization temp. of the steel. |
