| 摘要 |
PROBLEM TO BE SOLVED: To provide a forward extrusion forging method which eliminates or reduces occurrence of flash, can use dies or the like for a long period, and improves yielding and productivity. SOLUTION: An inclined edge 14 dented diagonally from the periphery of the tip face 12 and a recessed ring 16 adjacent to the edge 14 are installed on the tip face 12 of a punch 10 for pressing the rear end 2 of a cylindrical blank 1 inserted into an accommodation part 24 in a die 20'. When the punch 10 is brought into contact with the blank 1, the periphery on the rear end 2 of the blank 1 is fluidized towards the center by the inclined edge 14, and also the periphery on the rear end 2 of the blank 1 is expanded and fluidized in a diameter enlarging part 28 adjacent to the rear of the accommodation part 24 in the die 20'. Then, the blank 1 is extruded to a diameter reducing part 25 near the front in the die 20' so as to reduce the diameter.
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