| 摘要 |
PURPOSE:To form a piping joint with a press work without a skill fullness by folding back the face of the end part with inserting the second metal die into the expanded steel pipe end part after expanding the pipe so that the face of the end part can be inclined for the axial core with inserting the first metal die into the end part of a steel pipe. CONSTITUTION:A metal die 11 has a tapered face 11a and the diameter A of an inserting part is approximately same as the inner diameter of a steel pipe 10. The angle made by the tapered face 11a and the axial core of the steel pipe 10 is 45 deg.. The pipe expansion is then performed with inserting the metal die 11 into the end part 10a of the steel pipe 10 at the first step. a metal die 12 has the folded back face 12b which is at right angle to the axial core in continuation to a curved face 12a and also the diameter A of the inserting part is almost equal to the inner diameter of the steel pipe 10. And it is inserted into the end part 10a of the steel pipe 10 which is expanded by the metal die 12 at the second step. Then the face of the end part 10a is curved smoothly by the curved face 12a and further folded back at right angles to the axial core by the folded back face 12b and a pipe joint face is made. With inserting a loose flange 13 a joint is formed. |
