# Coefficient Of Thermal Expansion

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

ΔL = α × L × ΔT

where α is the coefficient of thermal expansion; L is the length of the metallic component; and ΔT is the change in temperature. The coefficient of thermal expansion is expressed in units of °C^{−1} in the SI system and °F^{−1} in US customary units. The table contains a partial listing of coefficients of thermal expansion for alloy and stainless steels.

*See also Thermal Expansion.*