High resistivity value of heating tube:

Electric heating alloy materials should first have a relatively high resistivity. The electric heating element made of high-resistivity material has high electrothermal conversion efficiency; the volume of the electric heating element is small; alloy materials are saved; high-power rapid heating can be realized. It is especially important when designing an electric heating furnace with high temperature, high power and small size.

When designing electric heating elements, in principle, high-temperature elements should be made of alloy materials with high resistivity, and low-temperature elements should be made of alloy materials with lower resistivity.