The disadvantage of iron-chromium-aluminum alloy is mainly low high temperature strength, and its plasticity increases with the increase of temperature. Above 1000°C, the material tends to slowly elongate due to its own weight, causing the element to deform. In addition, after being used at high temperature for a long time, after cooling with the furnace, it becomes brittle as the grain grows, and cannot be bent in a cold state. These shortcomings should be avoided and overcome in both design and use.
high temperature in the atmosphere
The maximum service temperature of HRE alloy in Fe-Cr-Al heating alloy can reach 1400℃, while the maximum service temperature of Cr20Ni80 alloy in Ni-Cr heating alloy is 1200℃.
long lasting
At the same higher use temperature in the atmosphere, the life of iron-chromium-aluminum components can be 2-4 times that of nickel-chromium components.
high surface load
Since the iron-chromium-aluminum alloy allows high temperature and long service life, the surface load of the element can also be higher, which not only makes the temperature rise faster, but also saves alloy materials.
Good antioxidant properties
The Al2O3 oxide film formed on the surface of the iron-chromium-aluminum alloy has a dense structure, good adhesion to the substrate, and is not easy to cause pollution due to scattering. In addition, Al2O3 has high resistivity and high melting point. These factors determine that the Al2O3 oxide film has excellent oxidation resistance. The carburization resistance is also better than that of Cr2O3 generated on the surface of nickel-chromium alloys.
small specific gravity
The specific gravity of Fe-Cr-Al alloys is smaller than that of Ni-Cr alloys, which means that Fe-Cr-Al uses less material than Ni-Cr to make equivalent components.
High resistivity
The resistivity of iron-chromium-aluminum alloy is higher than that of nickel-chromium alloy. When designing components, alloy materials with larger specifications can be selected, which is beneficial to prolong the service life of components, which is particularly important for thin alloy wires. When selecting materials of the same specification, the higher the resistivity, the more material is saved, and the smaller the position occupied by the components in the furnace. In addition, the resistivity of FeCrAl alloys is less affected by cold working and heat treatment than NiCr alloys.
Good sulfur resistance
It has good corrosion resistance to iron, chromium and aluminum when the sulfur-containing atmosphere and the surface are polluted by sulfur-containing substances, while nickel-chromium will be severely eroded.
cheap price
Since iron-chromium-aluminum does not contain the scarcer nickel, the price is much cheaper than nickel-chromium.