Expansion alloy generally according to the size of the expansion coefficient, can be divided into three types:

1, Low expansion alloy or call invar alloy, generally in 60 ~ 100 ℃ temperature range has a very small coefficient of expansion.

2, Settle or sealing alloy, alloy in commonly 70 ~ 500 ℃ temperature range with constant low or moderate expansion coefficient.

3, High expansion alloy, generally refers to at room temperature to 100 ℃ temperature range has a great deal of expansion coefficient of expansion alloy.