| 摘要 |
PURPOSE:To improve corrosion resistance by forming a 1st spacing between the inner peripheral surface of the tapered part of a cap body and the outer peripheral edge part of at the end of a cylindrical body, forming a 2nd spacing between the tapered part and the outer peripheral surface at the end part of the cylindrical body and completely filling these spacings by a molten metal when the tapered part is melted. CONSTITUTION:Since the 2nd annular spacing opening in an axial line direction is formed between the inside wall surface of the tapered part 14 and the outer peripheral surface of the end part 20b of the cylindrical body, the escape of heat from the tapered part to the cylindrical body side is prevented at the time of melting the tapered part by a welding arc. The complete melting of the tapered part is, therefore, possible and the remaining of the tapered part on the outside surface of the tank is obviated. Since the cylindrical body is disposed to face laterally, the molten metal moves to fill the annular 1st spacing between the end face at the end part of the cylindrical body and the wall surface having no tapered part if the tapered part is melted; thereafter, the molten metal is gathered to one by the surface tension and the smooth molten part is formed. The spacings are completely filled in this way and since the step part to be the cause for corrosion is not formed, the weld zone resistant to corrosion is formed. |
