Bimetal

Abstract

It is an object of the present invention to provide a bimetal having a same or wider proportional temperature range than a bimetal using a 42 wt % Ni--Fe alloy as a low thermal expansion alloy, and a higher bending characteristic of a large bending coefficient than a bimetal using a 36 wt % Ni--Fe alloy. The bimetal is formed by bonding a Ni--Co--Fe group low thermal expansion alloy, wherein a total amount of Ni and Co restricted to a very narrow containing range is within a specific composition range, a thermal expansion coefficient at 30 to 100.degree.C. is made similar to that of a 31 wt % Ni--5 wt % Co--Fe alloy of a nominal composition, a thermal expansion is very small and 2.times.10.sup.-6 /.degree.C. or less in the temperature range of 30.degree.to 300.degree. C., and further, a transition point is 250.degree. C. or higher and a transformation temperature is 50.degree. C. or less, and a high thermal expansion metal or alloy directly or via an intermediate metal or alloy whereby a stable and high precision thermal control can be realized in thermal control devices and the like, and it is possible to achieve the small-size, light and endurable devices, thus the bimetal can be used more widely.

Dependencies are inferred from the claim text.