text: The process was invented in Hanau, Germany in 1917. Heraeus Vacuumschmelze and Dr. Wilhelm Rohn applied for a patent on vacuum melting on 12 January 1918 and were granted a German patent DE 345161.
  Edwin Fitch Northrup built the first prototype of a vacuum induction furnace in the United States of America in 1920.
  Medium frequency furnaces were seen soon afterwards in England and Sweden in 1927.
  The process was initially developed to refine certain special metals such as cobalt and nickel. As these metals and alloys became more common, the process of VIM became more widely used.
  VIM now helps to melt a variety of metals for aircraft and nuclear applications.