| 摘要 |
PURPOSE:To apply high rolling reduction to a stock pipe of a circular section inserted internally with a mandrel or plug and to economically produce a pipe by engaging the stock pipe with circular cylindrical rollers and rolling the pipe with caliber rolls while the mandrel or plug is held inserted therein. CONSTITUTION:The mandrel 2 is inserted into the stock pipe 1 and is transferred from the upper stream side of the main direction to a screw down device 10. The pipe 1 engaged with the screw down device 10 is rolled according to an inter-roll distance. The rolled pipe 1 is reduced in thickness to an irregular section of an approximately square shape and is rolled by using the caliber rolls held inserted internally with the mandrel 2 or plug to form a product pipe having a circular section. The product pipe having the circular section is similarly obtd. by extrusion-blanking or drawing the stock pipe having irregular section by rolling with caller roll or by using a ring die. The high draft working of the stock pipe and the economical pipe production are thereby permitted. |
