What Does Alpha Iron Mean?
Alpha iron is an allotrope of iron with a body-centered cubic (BCC) crystalline structure. It is a ferromagnetic material that generates magnetic properties due to its crystalline nature. It is structurally stable below 910°C (1,670°F) and highly irregular after this upper temperature boundary. It can only dissolve a small concentration of carbon, no greater than 0.021% by mass.
Corrosionpedia Explains Alpha Iron
The addition of alloying metals can stabilize the body-centered cubic (BCC) structure, facilitating heat treatment of low-alloy steels. In the extreme case of low corrosion resistance steel, a much higher alloy content makes the structure stable at a wider range of temperatures. However, other metals if incorrectly chosen to form an alloy bond can destabilize the BCC structure and raise its eutectoid temperature.