摘要 |
A tank has an upper shell and a lower shell. The shells have flanges at their periphery which are seam-welded to form a tank. A plurality of projections formed on the flange of the upper shell and a plurality of recesses formed on the flange of the lower shell fit together thereby to prevent the flanges from displacing each other when they are seam-welded. Also, a method for making the tank is disclosed.
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