Method and apparatus for induction heating

The invention is a highly performing innovation-driven method of heating of the large steel workpiece by induction, allowing for high temperature uniformity and reduced treatment times.

Title of the patent Method and apparatus for induction heating
Thematic area Electrical, electronic and information engineering
Ownership Alma Mater Studiorum – Università di Bologna
Inventors Antonio Morandi, Massimo Fabbri
Protection Italy
Licensing status Available for licensing agreement
Keywords DC/AC coupling, induced voltage, current ripple, induction heating, magnetic metals, DC coil
Filed on Mar 23, 2017

High temperature uniformity is required in heating of large steel work-piece. The present invention involves applying both an AC field (via copper coils) and an intense DC magnetic field (via superconducting coils) which alters the magnetic properties of the material to be heated. Thus, a deeper penetration of the induced currents takes place and, therefore, a much more uniform heating is made possible.


  • production of semi-finished steel and steel processing
  • re-introduction of steel swarf into the production cycle



  • better performance in terms of productivity, treatment velocity, surface quality, control over the process
  • greater direct and indirect energy efficiency of the production process
  • no C02 emissions which are contrariwise present in industrial gas heaters
  • use of current instead of gas, possibility to use electricity generated from renewable sources