On the Chart of Thermal Expansion Coefficients of Dumet Wires

Abstract

It is very difficult to measure the longitudinal and radial expansion coefficients of Dumet wires in commercially used forms. It may therefore be useful to construct charts from which the thermal expansion curves are readily drawn if we know the copper ratio as well as the nickel content of the core metal. Using appropriate formulas for calculating expansion coefficients from the basic physical properties of copper and the core metal, we have made 8 such charts and also made 4 charts of mean expansion coefficients in the range of 30°C to 380°C and 0°C to 500°C. By use of these charts we can immediately select Dumet wires suitable to the glass used for manufacturing electric lamps, elctron tubes, etc.