| 摘要 |
PURPOSE:To produce a communicating pipe between a cylinder head and a muffler in short stages at a low cost without producing defective products by casting a bar having a forged annular flange part then punching the same. CONSTITUTION:A bar 6a having an annular flange part 4 is produced by cold forging, and in the stage of casting a cylinder head part with aluminum, the upper part of the bar 6 including the flange part 4 is cast, thence it is punched, whereby a communicating pipe 3 is obtained. Further, a muffler (not shown) is mounted to the other end of the pipe 3. It is also possible to reduce working time by casting the bar 6b which is beforehand punched by leaving a partition wall 5a for preventing the inflow of molten aluminum during ita casting in place of casting the bar 6a as it is. |
