Cold rolled strip with containing up to 6% Si and cold rolled and annealed to give specific magnetic properties and high electrical resistivity. They can be grain-oriented (GO) to give preferred magnetic properties in the rolled direction or non-grain oriented (NGO) to give uniform properties. The strips or laminations are usually lacquer coated to increase electrical resistivity when assembled into cores for transformers, electric motors, etc
A process in which molten steel is poured into a water-cooled copper mould for gradual solidification as it is drawn down the caster, turning into a solid steel billet, bloom, or slab. Compared to ingot casting, continuous casting has evolved as the preferred method for making semi-finished steel because of much better yield, productivity and cost performance
In metallurgy, it is most commonly used to harden steel by introducing martensite, in which case the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. In steel alloyed with metals such as nickel and manganese, the eutectoid temperature becomes much lower, but the kinetic barriers to phase transformation remain the same. This allows quenching to start at a lower temperature, making the process much easier. High speed steel also has added tungsten, which serves to raise kinetic barriers and give the illusion that the material has been cooled more rapidly than it really has. Even cooling such alloys slowly in air has most of the desired effects of quenching.
Extremely rapid cooling can prevent the formation of all crystal structure, resulting in amorphous metal or “metallic glass”.
Annealing: Heating to holding at a suitable temperature, followed by cooling at a suitable rate, for such purposes as:
improving cold working properties
obtaining a desired structure
When applicable, the more specific terms, full annealing, isothermal annealing or sub-critical annealing could be used:-
Full annealing. Heating to and holding at some temperature above the transformation range, followed by cooling slowly by the transformation range.
Isothermal Annealing. Heating to and holding at some temperature above the transformation range, then cooling to and holding at a suitable temperature until the austenite to pearlite transformation is complete, and finally cooling freely.
Sub-Critical Annealing. Heating to and holding at some temperature below the transformation range, followed by cooling at a suitable rate.