| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a Cu-Ni-Si based copper alloy sheet which has excellent fatigue resistance and a spring property even if used at high temperature and high oscillation environment for a long time after bending working of a prescribed shape as a raw material as a relay movable piece, a socket terminal or the like of various electric parts. <P>SOLUTION: The Cu-Ni-Si based copper alloy sheet includes 1.0-3.0 mass% of Ni; 1/6-1/4 concentration of Si based on Ni, and a rest consisting of Cu and inevitable impurities, wherein orientations of all pixel in a measured area of a surface are measured at 0.5 μm of a step size by an EBSD method, an area ratio of a crystal grain in which an average orientation difference among the all pixel in the crystal grain is less than 4° when a border in which an orientation difference between abutting pixel is at least 5° is made a crystal grain boundary is 45-55% of a measured area, an area average GAM of a crystal grain existing in an area to be measured is 0.8-1.6°, a number of a Ni-Si precipitated object particle in which a particle diameter exceeds 100 nm is 0.2-0.7 piece/μm<SP POS="POST">2</SP>, and a concentration of Si solid solved in a crystal grain is 0.1-0.4 mass%. <P>COPYRIGHT: (C)2012,JPO&INPIT |
