Reinforcement steel

Abstract

A reinforcement steel bar includes a shaft part and a head part formed by forging an end portion of the shaft part. A front end surface with its normal direction aligned with an axial direction of the shaft part is formed at a front end portion of the head part. A base end portion of the head part projects from the shaft part in a radial direction of the shaft part. A plate-shaped flange portion is formed at an outer peripheral part of the base end portion of the head part.

1 . A reinforcement steel comprising:
 a shaft part; and   a forged head part provided at an end portion of the shaft part, wherein   a front end surface with a normal direction aligned with an axial direction of the shaft part is formed at a front end portion of the head part,   a base end portion of the head part projects from the shaft part in a radial direction of the shaft part,   a plate-shaped flange portion is provided at an outer peripheral part of the base end portion of the head part, and   grid ribs are provided on an outer peripheral surface of the shaft part.   
     
     
         2 . The reinforcement steel according to  claim 1 , wherein
 the front end surface is located at a concentric position with the shaft part, and   an outer edge portion of the front end surface is located outside, in a radial direction of the shaft part, of a corner portion between a base end surface of the base end portion and an outer peripheral surface of the shaft part.   
     
     
         3 . The reinforcement steel according to  claim 2 , wherein the corner portion has a curved surface. 
     
     
         4 . The reinforcement steel according to  claim 2 , wherein a recess is formed along the corner portion. 
     
     
         5 . The reinforcement steel according to  claim 1 , wherein a flat surface is provided on the front end and base end portions of the head part, and the flat surface is parallel to the axial direction of the shaft part. 
     
     
         6 . The reinforcement steel according to  claim 5 , wherein a distance from a shaft center of the shaft part to the flat surface is in a range from 0.5 to 0.7 times as large as a diameter of the shaft part. 
     
     
         7 . The reinforcement steel according to  claim 1 , wherein a linearly extending protrusion is provided along an outer surface of the head part. 
     
     
         8 . (canceled)