The magnetic annealing is a particular kind of heat treatment, the ultimate aim of which is to eliminate the residual magnetism, which may be present on some final products of machining, from ferrous parts.
This kind of heat treatment takes place in vacuum, ie in an oven in which each type of atmosphere is removed before carrying out the heating and the reaction (see the article on the atmospheres of the furnaces); the magnetic annealing treatment usually involves the following steps :
- a slow heating up to the temperature of the pieces chosen
- maintaining at this temperature for a period ranging from 2 to 6 hours
- controlled cooling up to about 500 ° C
- slow cooling down to 300 ° C
- rapid cooling below 100 ° C
These temperatures and treatment durations are, of course, vary depending on the kind of objects and their shapes.
In general, using the magnetic annealing for the manufacture of components for printers, relais, laminations for transformers and other parts that require a magnetic charge neutral or predetermined to operate.