Vacuum melting is the first step in manufacturing nitinol. The nickel and titanium and any other materials are placed in a crucible and then melted under high vacuum or ultra high vacuum. Once cooled, the solidified material, called ingot, is ready to be rolled into bar or sheet or drawn into wire. Ensuring the melt quality is critical to obtain high quality finished products. In order to do this, two different melting technologies are used: VIM and VAR.
Vacuum Induction Melting (VIM): The first step of ingot production is vacuum induction melting (VIM). The crucible is placed within an induction coil and high frequency AC electricity energizes the coil. The AC electricity induces eddy currents in the metals in the crucible, heating them to their melting temperature. One of the advantages of VIM is that, by controlling the frequency of the electricity, the metal can be stirred to obtain a high degree of consistency.
Vacuum Arc Remelting (VAR): Often, in order to obtain the highest possible ingot quality, the freshly cooled ingot will be transferred to a VAR. Here, an arc is struck between a tungsten electrode and the ingot. The process is very similar to TIG welding, except that it happens under vacuum. In the VAR, the ingot can be remelted as many times as necessary to obtain the quality and consistency that is required.
At Kellogg’s Research Labs, we have both VIM and VAR to support your needs. Melting furnaces are specified by maximum ingot size. Our current melting equipment consists of:
- 5 pound VIM
- 3 pound VAR
- 60 pound VIM
- 325 pound VIM
- 550 pound VIM
- 1 ton VAR
If you are interested in custom melted nitinol, please feel free to contact your applications engineer at 855-583-5353 or Nitinol@KelloggsResearchLabs.com to get started.Request A Quote