| 摘要 |
PURPOSE:To obtain a hollow valve whose head part and cover have been brought to pressure welding by hot forging, by pressing the cover into the head part of a valve body in which a hollow hole part has been formed, and thereafter, heating the head part to a hot forging temperature area, and executing the forging. CONSTITUTION:A valve body 2 is made by working a hollow hole part in a valve-shaped base material 1 which has been formed by hot forging, and the inside of a head part 3 is finished precisely to match a size of a cover 4. The cover 4 which has provided a notch 5 on the outside peripheral part is pressed into the shade part 3, and thereafter, the head part is heated to a hot forging temperature area, and hot forging is executed by a die 7 and a punch 8. In this way, a hollow valve whose head part and cover have been brought to pressure welding by hot forging can be manufactured.
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