There are mainly two kinds of materials for electric heating alloy wire: fe-Cr alloy wire and Ni-Cr alloy wire, the former belongs to the ferrite structure of the alloy material, the latter belongs to the austenite structure of the alloy material, in addition, there are some special use of electric thermal alloy wire, such as tungsten wire, molybdenum wire, etc.
The characteristics of fe-Cr alloy wire are as follows:
(1) High service temperature such as HRE ferrochrome aluminum alloy wire in the atmosphere the highest service temperature up to 140℃;
Long service life;
(3) The allowable surface load is large;
(4) Good oxidation resistance, which generates Al2O3 after oxidation. The film has good oxidation resistance and high resistivity.
Specific gravity is less than linear chromium alloy;
Good sulfur resistance:
@ price is significantly lower than nickel-chromium alloy;
The disadvantage of @ is that it exhibits plasticity with increasing temperature, and its strength is low at high temperature.
The characteristics of Ni-Cr alloy wire are:
(1) Ni-cr electrothermal alloy is characterized by high strength at high temperature;
(2) after long-term use and then cold, the material will not become brittle;
(3) The radiation rate of the fully oxidized ni-Cr alloy is higher than that of the fe-Cr aluminum alloy.
The chemical composition and properties of commonly used electric heating alloys Electric heating alloy wire is the most widely used and the largest amount of heating material. Its disadvantage is that it is at a very high temperature (hot state) under working conditions, and it is prone to oxidation reaction and burn out in the air; from the perspective of electrothermal energy conversion, energy loss due to the generation of visible light; electrothermal alloy wire It is often used in a spiral state, which will produce an inductive reactance effect when energized.