TWO-PIECE CAN MADE OF SURFACE TREATED STEEL SHEET AND ITS MANUFACTURE

PURPOSE:To permit the application of surface treating method excellent in anti-corrosion performance by partially plating at least the ground contact part of a can made of steel plate with a tin-zinc alloy containing a specific amount of the zinc. CONSTITUTION:The surface of the ground contact part 10 of two-piece can 1 made of surface treated steel sheet is partially plated with a tin-zinc alloy containing a 2 - 20wt.% zinc. The plating with the tin alone, in the case of exposed steel surface due to the damage to the plated surface, will not protect the steel from the corrosive effect of such damage at the sacrifice of the tin, eventually resulting in the corrosion of the steel. The application of the anti- corrosion method in the increased amount of the tin is uneconomical with a reduction in the operational efficiency due to a longer plating time required. On the other hand, the plating with the zinc alone, although capable of protecting the steel against corrosion at the sacrifice of the zinc, elutes the zinc abnormally in a short time due to a large potential difference between the iron and zinc and, therefore, a long serviceability cannot be expected. The zinc is also liable to white corrosion with unsightly finish appearance.