Hydrogen Annealing

Vac-Met has a long history of specialty heat treating processes like hydrogen annealing various electrical magnetic steel materials for the aerospace, energy and automotive industries.

Vac-Met anneals typically materials such as Carpenter 49, HYMU 80, MUMETAL, 4750 Nickel Iron and Hiperco 50. These specialty magnetic hydrogen anneals have been processed to OEM specifications such as Honeywell, Woodward and Moog. With the right hydrogen anneal a proper microstructure can be formed which develops excellent magnetic properties such as high saturation magnetization, high permeability, and also which renders a small hysteresis loop.

Electrical magnetic materials must have these key characteristics for their application:

  • High saturation magnetization, which permits the material to do the most work
  • High permeability with small imposed fields
  • Small coercive force
  • A small remanence, so no magnetism remains when the field is removed

These preceding characteristics also lead to a small hysteresis loop thereby minimizing energy losses while in operation. Some developed electrical soft magnetic materials like silicon iron electrical steels, high nickel irons or specialty cobalt irons have been allowed to allow these materials to have different magnetic properties for specific electrical applications.

Magnetic annealing of electrical magnetic materials often called soft magnets involves a designed high temperature anneal. Some of the magnetic anneals are performed in a vacuum atmosphere but many are performed in a hydrogen atmosphere at a controlled cooling rate to develop the proper microstructure to meet the required magnetic properties

A microstructure after the final manufacturing process such as mechanical cut laminations must be free of residual stresses, cold work, and have a coarse ferritic grain structure in addition to a non-oriented grain structure typically required for the silicon electrical steels.

Vac-Met, Inc. has a long history of performing these specialty magnetic annealing processes to each of the specifications for the automotive, aerospace, and energy industries. These specialty magnetic hydrogen anneals are for such OEMs and applicable specifications as Honeywell, Woodward, and Moog.

Typical Materials

Carpenter 49
HYMU 80
MUMETAL
4750 Nickel Iron Alloy
Hiperco 50
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