# Coefficient Of Thermal Expansion

The ratio of the fractional change (Î”L/L) in the size of a material to its change in temperature, typically represented by the symbol Î± (alpha) for solids and Î² (beta) for liquids. In metals, the change in length (Î”L) is given by the following formula:

Î”L = Î± Ã— L Ã— Î”T

where Î± is the coefficient of thermal expansion; L is the length of the metallic component; and Î”T is the change in temperature. The coefficient of thermal expansion is expressed in units of Â°C^{âˆ’1}Â in the SI system and Â°F^{âˆ’1}Â in US customary units. The table contains a partial listing of coefficients of thermal expansion for alloy and stainless steels.

*See also Thermal Expansion.*