This specification covers wrought iron-silicon (Fe-Si) steels that are generally used in the manufacture of electromechanical devices, such as relays and solenoids, requiring higher electrical resistivity, higher permeability, and lower coercivity and residual magnetism than provided by either carbon steels or soft magnetic low-carbon irons. The steels covered in this specification are Steel type2 1, 1F, 2, 2F, 3. This specification covers steels in the form and condition required for fabrication into parts. The chemical composition requirements shall conform in carbon, manganese, silicon, phosphorus, sulfur, aluminum, and iron. Available forms and conditions are forging billet, hot-rolled product, cold-finished bars, strip, and wire. The material shall undergo heat treatment before performing conventional dc magnetic testing and shall conform to the required coercive force and coercive field strength.

1.1 This specification covers wrought iron-silicon (Fe-Si) steels that are generally used in the manufacture of electromechanical devices, such as relays and solenoids, requiring higher electrical resistivity, higher permeability, and lower coercivity and residual magnetism than provided by either carbon steels or soft magnetic low-carbon irons. The steels covered in this specification are:

Steel Type

Nominal Composition

1

1.1 % Si-Fe

1F

1.1 % Si-Fe free machining

2

2.3 % Si-Fe

2F

2.3 % Si-Fe free machining

3

4.0 % Si-Fe

1.2 This specification covers steels in the form and condition required for fabrication into parts. The fabricated parts typically require a final heat treatment to obtain the desired magnetic performance. The term mill annealed as used in this specification applies to a heat treatment, typically applied by the producer, intended to improve formability. The mill anneal does not provide the optimum magnetic performance and is not intended to replace the need for the finish annealing of parts.

1.3 This specification covers steels in the form of forging billets, hot-rolled bar and strip, cold-finished bar, wire, and cold-rolled strip in thicknesses up to 0.250 in. (6.35 mm).

1.4 This specification does not cover electrical sheet steels used in transformer and motor laminations.

1.5 This specification does not cover powder metallurgy materials capable of being processed into magnetic core components having similar silicon contents.

1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.