| ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ KAWASAKI STEEL TECHNICAL REPORT No.42 ( May 2000 ) ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ |
| Formable Hard and Soft Tempered Ultra-thin
Sheet Steels for Can Use Akio Tosaka, Kaneharu Okuda, Masatoshi Aratani |
| Synopsis: A method which uses a highly efficient continuous annealing process for manufacturing hard- or soft-tempered ultra-thin steel sheets (in mill black plates) having excellent formability, for cans, has been developed. It has become clear that soft-tempered black plates of T1 toT2 grades, having excellent formability, can be manufactured by the use of an ultra-low carbon steel, even with a rapid heating-and-cooling continuous annealing process, whereas, a rather harder T2.5 to T3 grade black plates are similarly manufactured by adding a small amount of a solid-solution strengthening element, Mn, to the same ultra-low carbon steel. These newly developed black plates are superior in deep-drawing formability, elongation and flanging property and are expected to contribute to the lessening of material sheet thickness. Stable production of hard tempered black plates of T5 or greater grade can be conducted by adding N. The added N, by its solid-solution hardening and strain-aging hardening phenomena, effectively contributes to the increase of can-body strength and this enables the reduction of material plate thickness. Fluting (bending pattern), occurring during cylinder-shape forming, has been found to be avoided by effectively using the history of the working conditions of canmaking process. |
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