| 摘要 |
PURPOSE:To enable the sufficient corrosion prevention of the bottom board of a tank, at the time of forming a bottom board by welding a steel sheet coated with a low potential metal, by using steel with an approximately H shape partially coated with a low potential metal on the joint part of the steel sheet for the bottom board of the tank. CONSTITUTION:For example, the lower face of the rear side of the steel sheet 1 for the bottom board of the tank is thermal-sprayed with zinc to form sprayed deposition 4. Furthermore, the whole circumferential face of a lower flange 6 of the steel having an H cross sectional shape is thermal-sprayed with zinc to form sprayed deposition 5, by which a corrosion preventing joint 2 is constituted. In this way, the whole face of the bottom board of the tank in contact with the fundamental soil of the tank is coated with the sprayed deposition of zinc. Next, the steel sheet 1 for the bottom board of the tank is inserted into the grooves of both sides of the corrosion preventing joint 2, and the edge parts on both sides of an upper flange 7 of the corrosion preventing joint 2 and the upper face of the steel sheet 1 for the bottom board of the tank are applied with bead welding to form a weld bead zone 3 positioned on the inner side of the tank. In this way, the bottom board of the tank can be constituted only by lap welding and also as the whole body of the rear of the bottom board of the tank can be coated with the sprayed coating of zinc, by which its corrosion preventing can sufficiently be executed. |
