METHOD AND APPARATUS FOR MANUFACTURING HOLLOW BODY AND TUBE MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To make a tube length and a wall thickness of the tube end after the fixed diameter rolling coincide with the target value with high accuracy. SOLUTION: After a drawing rolling to reduce the wall thickness as well as increasing the length of a hollow raw tube 40 in accordance with the predetermined drawing rolling conditions based on the final target dimension of the hollow raw tube 40 is performed, the outside dimension of the tube 42 rolled by drawing in accordance with the predetermined sizing rolling conditions based on the final target dimension is approximated or made to coincide with the target value through the sizing rolling, whose procedures are executed sequentially on a plurality of hollow raw tubes 40. At this time, the predetermined drawing rolling conditions are changed based on the outside diameters of the tube 42 after the sizing rolling is performed.