| 摘要 |
PURPOSE:To improve the seam weldability of a surface-treated steel sheet for can manufacture by undercoating both sides of a steel sheet with a very small amount of Ni, forming Sn coating layers, and carrying out chromating. CONSTITUTION:A steel sheet is cleaned, and Ni coating layers are formed on both sides of the sheet by electroplating or other method by 2-30mg/m<2> per one side. Sn coating layers are formed on the Ni coating layers by electroplating or other method by 200-1,000mg/m<2> per one side. Chromate layers are then formed on the upper layers. Since said very small amount of Ni is deposited, residual free Sn can be ensured for the resulting very thin tin plate after a stage for baking a paint film when a can is manufactured, so high seam weldability is provided. Since a dense Sn-Ni alloy is formed, the corrosion resistance can be improved. |
