MANUFACTURING METHOD FOR HOLLOW THREADED-RIB DEFORMED STEEL BAR

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method for hollow treaded-rib deformed bar steel which facilitates separating a metallic core through a metallic core means. SOLUTION: A manufacturing method of a hollow threaded-rib deformed steel bar characterized by the features that in the method of manufacturing deformed steel bar having a threaded-rib projection in the outer diameter through the hot rolling of a bloom filled in by a steel of different quality in the corresponding portion of the aperture of the bloom by locating a series of round apertures in the axial direction in the central part of the bloom section of the raw material, the finishing temperature in the hot rolling is not less than 900 degree C. and then the deformed steel bar and the metallic core of the steel of different quality are separated.