Electric furnace for thermochemical treatment of metal workpieces - where electromagnets are used to provide strong magnetic field in muffle fed with reaction gas

摘要

The furnace has an outer ring casing with a vertical axis, made of electrical steel sheet and forming a magnet yoke. Inside the casing are magnet cores carrying electromagnet coils and bolted to the casing. Each core carries a pole piece directing the magnetic field into an axial muffle in the furnace. The pole pieces are aligned at 90 deg. w.r.t. each other. The muffle is pref. provided on its outer surface with an electric heating element formed by a bifilar winding. The furnace can be used e.g. for gas nitriding, carbonitriding, carburising, etc. A variety of processes can be carried out in an adjustable magnetic field.