| 摘要 |
PURPOSE:To reduce and remove stuck scale simultaneously with decarburization by cold rolling a steel plate which is held stuck with hot rolling scale then subjecting the same to box annealing in the tight coil state in a non-oxidative atmosphere. CONSTITUTION:A steel plate which is held stuck with hot rolling scale is subjected to direct cold rolling under good rolling lubrication, whereby the steel plate of black surfaces covered with fine powder scale is obtained. Thence, this steel plate is held in the tight coil state and is subjected to box annealing in a non-oxidative atmosphere. The annealing temps. are kept at >=550 deg.C. Thereby, the black scale is reduced together with the decarburization of the carbon in the steel, whereby the scale-free steel plate is obtained. If the content of carbon in the steel is excessively small, the sufficient reduction does not take place and therefore about >=0.005wt% is the preferable content of carbon. If necessary, the steel plate may be subjected to skin pass rolling. |
