| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a steel wire for a cold formed spring having excellent cold cuttability and fatigue properties. <P>SOLUTION: The steel wire for a cold formed spring satisfies a prescribed componential composition, and has a metallic structure where the average particle diameter [√(ab)] of spherical carbides in which an aspect ratio [a/b wherein the major width of carbides is denoted as a, and the minor width is denoted as b] is ≤2 satisfies ≤1.0 μm, the ratio (area%) of the spherical carbides occupied in the steel satisfies (0.1 to 3)×the content (mass%) of C in the steel, the content (mass%) of Cr forming the spherical carbides satisfies ≤[0.4×the content (mass%) of Cr in the steel], further, hardenability multiple (Dic) shown in prescribed equations (1) to (3) lies in the range of 110 to 450 mm, and also, its tensile strength is ≥2,000 MPa. <P>COPYRIGHT: (C)2007,JPO&INPIT |
