| 摘要 |
PURPOSE:To form with a high yield a hollow spherical article having a high strength by forming a bossed discoid formed body which has been brought to rotational forging from a billet base material, to a cup-shaped formed body by deep drawing, and thereafter, performing mouth drawing by rotational forging to its aperture end. CONSTITUTION:A discoid formed body 3 having a boss 31 in the center part is worked from a discoid billet base material 1 by a rotational forging machine 2, and thereafter, moreover, deep drawing by a press 4 is performed, and a cup-shaped formed body 5 is made. Subsequently, by a rotational forging machine 6 consisting of a punch 61 and a die 62, mouth drawing is performed to an aperture end of the formed body 5, and an aperture boss part 72 and a closed boss part 71 are formed. In this way, a bossed hollow spherical article having a high strength can be formed with a high yield.
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