| 摘要 |
PROBLEM TO BE SOLVED: To provide an alloy having an extremely low thermal expansion rate.SOLUTION: There is provided an ultra low thermal expansion alloy having a component composition containing, by mass%, Ni:31.0 to 33.5% and Co:4.0 to 6.5% and the balance Fe with inevitable impurities and a structure having a ratio between a maximum value and a minimum value of a Ni percentage content measured by a line analysis using EPMA at any position of 1.05 or less. |
