The advantage and disadvantage of Fe Cr Al electric heating alloy
Advantages of Fe Cr Al electric heating alloy:
1. The maximum operating temperature of HRE alloy of Fe Cr al electric heating alloy is 1400 ℃, while that of Cr20Ni80 alloy of Ni Cr electric heating alloy is 1200 ℃.
2. Under the same high operating temperature in the atmosphere, the service life of Fe Cr Al alloy elements can be 2-4 times of that of Ni Cr elements.
3. As Fe Cr Al alloy is allowed to be used at high temperature and with long service life, the surface load of elements can also be higher, which not only makes the temperature rise faster, but also saves alloy materials.
4. The structure of Al2O3 oxide film on the surface of Fe Cr Al alloy is compact, which has good adhesion with the matrix and is not easy to cause pollution due to scattering. In addition, the high resistivity and melting point of Al203 decide that the oxidation film of Al203 has excellent oxidation resistance. The anti-carburizing is also better than that of Cr2O3 formed on the surface of Ni Cr alloy.
5. The proportion of Fe Cr Al is smaller than that of Ni Cr alloy, which means that the material of Fe Cr Al is less than that of Ni Cr alloy when making the equivalent elements.
6. The resistivity of Fe Cr Al alloy is higher than that of Ni Cr alloy, and larger size alloy materials can be selected in the design of elements, which is conducive to extending the service life of elements, especially for fine alloy wire. When the same material is selected, the higher the resistivity, the less material will be used, and the smaller the position of components in the furnace will be. In addition, the resistivity of Fe Cr Al alloy is less affected by cold working and heat treatment than that of Ni Cr alloy.
7. Fe Cr Al has good corrosion resistance when sulfur atmosphere and surface are polluted by sulfur substances, while Ni Cr will be seriously eroded.
8. The price of Fe Cr Al is much cheaper than that of Ni Cr because it does not contain the scarce nickel.
Disadvantages of Fe Cr Al electric heating alloy:
The main disadvantage of Fe Cr Al alloy is its low strength at high temperature, and its plasticity increases with the increase of temperature. When the temperature is above 1000 ℃, the material will stretch slowly due to its own weight, which will cause the deformation of the elements. In addition, after being used for a long time at high temperature and cooled in the furnace, it becomes brittle with grain growth, and can not be bent in cold state. These shortcomings should be avoided and overcome in design and use.