| 摘要 |
A superalloy with a low thermal expansion coefficient has of 0.1% or less of C, 1.0% of less or Si, 1.0% or less of Mn, 0.5 to 2.5% of Ti, more than 3.0% and not more than 6.0% of Nb, 0.01% or less of B, 20 to 32% of Ni and more than 16% and not more than 30% of Co within a range of 48.8</=1.235xNi+Co<55.8, and the balance essentially Fe except for incidental impurities. The superalloy may further contain 1.0% or less of Al, and has a mean coefficient of thermal expansion of 7.0x10-6/ DEG C. or less from room temperatures to 400 DEG C., a tensile strength of 100 kgf/mm2 or more at 500 DEG C., and a notch rupture strength superior to a smooth rupture strength in a creep rupture test at 500 DEG C.
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