METHOD OF PROCESSING CONNECTING ENDS OF DEFORMED STEEL BAR USED FOR REINFORCING CONCRETE, AND DEFORMED STEEL BAR PROCESSED BY THIS METHOD

摘要

A method of processing the connecting ends of deformed steel bars used for reinforcing concrete, comprising the steps of either machining a raw material for a deformed steel bar and forming rolled threads in the ribs and nodes or swaging the connecting end of the deformed steel bar to provide a greater diameter than that of a barrel and forming rolled threads therein, thereby improving the mechanical strength and faciliting processing while retaining the intrinsic fiber structure of deformed steel bars and the processing cost is greatly reduced; and a deformed steel bar obtained by this method. While cold swaging is performed such that a predetermined region on the side associated with the connecting end of at least one deformed steel bar having transverse ribs and a number of circumferential nodes on its cylindrical barrel surface is plastically deformed at ordinary temperature, the method includes a first stage for processing the transverse ribs and circumferential nodes to have a diameter greater than that of the cylindrical barrel by a predetermined amount, and a second stage for forming a threaded portion by rolling a predetermined region on the side associated with the connecting end of the swaged, deformed steel bar.