Generally the FeCrAl heating Alloys have similar basic chemical composition of 20-25% chromium, 4.5 to 6% aluminum and remaining iron. Other elements are Yttrium and silicon.

Properties of FeCrAl

The FeCrAl alloys can be processed at temperatures up to 1250oC offering resistance temperature about 1300oC. They possess ferrite structure. Subsequent to fine processing of alloy at high temperature, grain precipitation development of chromium carbide occurs at the welded points. It gives rise to resistance embrittlement when FeCrAl alloys is used at ambient temperature limits.

Corrosion Protection

The whole ranges of FeCrAl heating Alloy produce security layer of alumina in the oxidizing conditions. The alumina coating renovates by own when concentration of aluminum is 2%. The use of aluminum is interfered while scaling resistance of oxide layer when it is kept to thermal gradient.  By adding Yttrium, life of oxide layer is enhanced that results into increased scaling resistance.

The insufficient aluminum content offers the production of new oxide layer that novel chromium oxide layer is formed on the surface. The degradation resistance improves with increase in temperature however the chromium oxide coating becomes volatile at temperature more than 1100oC.

Atmospheric Limitations

1.The behavior of FeCrAl alloy is acceptable in absence of nickel in sulfur conditions.

2. FeCrAl heating Alloy is not preferred in nitration conditions because of production of chromium and aluminum nitrates that can reduce the corrosion resistance rapidly.

3. In the presence of water, FeCrAl alloy becomes toxic due to production of ferric oxides at high temperatures up to 1000oC.

4. In nitrogenous conditions, the operating temperature should not be more than 950oC. But preoxidation can increase the life of alloy if it is done regularly.  

5. In the carburing conditions, the preoxidized resistance can perform well.

6. The operation temperature should be limited to 1400oC in the presence of hydrogen ( 100oC or 75% broken ammonia)

7. In endothermic and exothermic conditions, the alloy temperature should be controlled to 1150oC.

8. In vacuum conditions, FeCrAl heating Alloy Wire temperature should be limited to 1000oC however the level of vacuum may change the controlled temperature limit.