| 摘要 |
PURPOSE:To obtain a required long-sized and thin-walled cylindrical blank material with high accuracy and high efficiency by inserting a mandrel into a cylindrical blank material, forming the material by pressing from the outside circumferential side and cooling the material after heating then removing the mandrel. CONSTITUTION:A cooled mandrel 2 is inserted into a heated cylindrical blank material 1 which is thick-walled and has a cylindrical shape. The material 1 is pressed and formed from the outside circumferential side thereof by using a pair of pressing means 3, 3 to roll and forge integrally the material 1 on the mandrel 2. The material in the forged state is heated in a furnace 5 and after cooling the mandrel 2 is removed from the worked cylindrical material 10 having a thin wall and a cylindrical shape. The material 10 having substantial strength is obtd. with good accuracy by the above-mentioned method. |
