| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wire steel or a bar steel that has excellent cold workability even when heat treatment such as spheroidizing is omitted and the steel is in a hot-rolled state and that can be manufactured by actual equipment, and particularly, to provide a wire steel or a bar steel can reduce dynamic strain ageing and reduce deformation resistance of steel in a process heat generation area even when the steel has a high deformation resistance at room temperature. <P>SOLUTION: The steel includes N, B and Ti satisfying an expression (1): -0.0060≤[N]-1.3×[B]-0.29×[Ti]≤0.0020, wherein [ ] represents the content of each element, and the balance iron and unavoidable impurities. The steel has a mixture structure of ferrite and pearlite, in which grain numbers of the ferrite present in a range from the center of the steel to a position of D/8, wherein D is the diameter of the steel, are from 6 to 12. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
