From standard IEC 60287-1-1 Ed.2.1 per K at 20°C.

Symbol
$\alpha_{\mathrm{ar}}$
Unit
1/K
Related
$a_{\mathrm{constr}}$
Used in
$\beta_{\mathrm{ar}}$
$R_{\mathrm{A_{\mathrm{1}}}}$
$R_{\mathrm{A_{\mathrm{2}}}}$
Choices
ConstructionValue
SWR0.0045
SWF0.0045
ST0.0045
SSR0.001
SSF0.001
CuWR0.00393
CuWF0.00393
BrzWR0.003
BrsWR0.0019
AlWR0.00403
TECK0.00403