| 摘要 |
The invention describes a method and an apparatus for the production of tear lines 5, 6, 7 on tear-open lids 2 of cans, making possible the use of thin tinplate. The tinplate is annealed for a short time along the tear line and is then quenched by means of a refrigerant. The changes in structure allow the can to be torn open easily. The annealing operation is performed with apparatuses conventional in spot welding, the electric current being chosen so that an annealing process occurs rather than fusion. <IMAGE>
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