Among metals, there are those that have the properties of magnetization. These include iron, nickel and cob alt. Gadolinium acquires ferromagnetic properties at temperatures below 0 оС. When these elements are added to the alloy, magnetic steel is obtained. In addition, they are characterized by the presence of residual induction and coercive force.
Magnetic steels and alloys
All alloys with magnetism can be divided into 2 types:
- hard magnetic;
- soft magnetic.
Hard steels comply with GOST 6862-71 and permanent magnets are produced from them. For this, high-carbon substances alloyed with chromium or chromium and cob alt are used.
Iron-based alloys can also be used to produce constant field magnets. An example would be alnico, where 54% is iron.
Soft magnetic - this is another name for electrical steels. They must comply with GOST 21427-75. Such magnetic steels are used to work invariable fields, where magnetization occurs without interruption. Hard magnetic materials have a significant residual induction, high coercive force. Low magnetic permeability becomes an additional property of the alloy.
The cores of coils of electromagnets and transformers are made from the material. Silicon and low carbon alloys are suitable for this.
Magnetic steel is marked with a four-digit number. The first number determines the structure and type of rolling. The second is the silicon content. The third number determines the heat loss, the fourth - the code of the normalized parameter.
For work in variable fields, you can use magnetic steel based on iron or nickel. An example of such material is alsifer.
To reduce electrical losses, an increase in resistivity is used. Magnetic steel plays an important role in modern manufacturing. Magnetic materials - ferrites have great resistance.
Ferrites are produced from oxides by powder metallurgy. Such materials have the properties of a ferromagnet and dielectric, which allows them to be used where high and ultrahigh frequencies are used.
The cost of ferritic cores is lower than others due to production automation. Alloys can be divided into 4 groups:
- press magnets.
Magnetic steel for permanentThe magnet must have a sufficient volume of carbon, which is in solid solution. Such alloys are called wrought. High-carbon materials are considered the simplest and cheapest. The addition of cob alt increases the magnetic properties of steel.
Cast alloys are based on Fe-Ni-A1. More than 80% of magnets are made from this material. The highest quality alloys of this group have very powerful magnetism. They are different from carbon and chromium magnetic steel.
Small magnets are produced by sintering. This will require nickel, aluminum and high purity iron. They are famous for their high hardness. This method creates magnets from magnetically hard ferrites. Barium ferrites are the most popular due to their high magnetic properties and reasonable price.