ASTM A867 - Iron-silicon alloys are also called silicon-core iron, electrical steels, rolling steels, silicon electrical steels, silicon steels, relay steels, or transformer steels. It is an iron alloy adapted to produce specific magnetic properties.
Iron-silicon (Fe-Si) alloys are frequently used in applications requiring higher electrical resistivity, higher permeability, lower coercive force, and residual magnetism, such as the manufacturing of electromechanical devices.
The steels contemplated in this specification are:
| Degree | Steel type | Alternative description | Nominal composition |
| FeSi1 | ASTM A867 – TYPE 1 | Silicon Core Iron "A" | 1.1% Si-Fe |
| FeSi1P | ASTM A867 – TYPE 1F | Silicon Core Iron "A-FM" | 1.1% Si-Fe free machining |
| FeSi3 | ASTM A867 – TYPE 2 | Silicon Core Iron "B" | 2.3% Si-Fe |
| FeSi3P | ASTM A867 – TYPE 2F | Silicon Core Iron "B-FM" | 2.3% Si-Fe free machining |
| FeSi4 | ASTM A867 – TYPE 3 | Silicon Core Iron "C" | 4.0 % Si-Fe |
Silicon irons (Fe-Si) are classified based on the silicon content present in chemical analysis according to ASTM A867 standard classifications. Each grade has its option of improved machinability when requested.
They are prone to rust, so a protective coating should be applied to heat-treated parts.
The forms in which it is available are: Strip, Bar, Plate and Wire. (Other shapes available upon request)
Due to their high magnetic properties, iron-silicon steels are mainly used in the manufacture of relays, solenoids, fans and injector parts.
