Vacuum-remelted process

Induction Furnace. The high frequency coreless induction furnace is used in the production of complex, high quaUty alloys such as tool steels. It is used also for remelting scrap from fine steels produced in arc furnaces, for melting chrome—nickel alloys and high manganese scrap, and more recentiy for vacuum steelmaking processes. 

Terbium metal is obtained from its anhydrous trifluoride, TbFs, or trichloride, TbCls, by thermal reduction with calcium, carried out in a tantalum crucible. Terbium produced by such methods may contain traces of calcium and tantalum. High purity metal can be prepared by various methods such as vacuum remelting, distillation, amalgam formation, floating zone melting, and various chemical processes. 

Commercially available metals (typically in the form of ingots, rods, slugs, etc.) often contain volatile or gaseous impurities associated with the refining process, which can cause the sample to erupt when using electron-beam evaporation. Thus, while it is possible to purchase vacuum-remelted evaporation slugs (at considerable expense), premelting of any metal, which melts before evaporation, in a separate operation prior to the co-condensation experiment, is advisable. 

V-Loc 180 wound closure device, 392 vacuum-remelted (VM) process, 304 Valiant devices, 653-6 Valsalva aortic root graft, 454 Valsalva sinuses, 486 Vascufll monofilament, 295 vascular endothelial growth factor (VEGF),467... 

Nickel-titanium solid SMAs are manufactured by a double-vacuum melting process to ensure the quality, purity, and properties of the final material. After the formulation of raw materials, the alloy is vacuum-induction melted at 1400°C. After the initial melting, the alloy transition temperature must be controlled due to the sensitivity of the transition temperature to small changes in the alloy chemistry. This is followed by vacuum-arc remelting to... 

Chemical compositions plus processing and heat treatment schedules relative to Inconel 718 and Udimet 718 are presented in Tables I and II. Hardness and ASTM grain size (average numbers) are included in Table II. Both the Inconel 718 and Udimet 718 superalloys were obtained as large-diameter (29 cm and 26 cm, respectively) hot-finished forging billets, vacuum-induction-melted and vacuum-arc-remelted (VIM-VAR). The two alloys have comparable chemical compositions, but the Inconel 718 has a significantly higher silicon content. 

Process code HIP, hot isostatically pressed at 1200 C, 69 MPa for 2 hr. VIM, vacuum induction melted. VAR, vacuum arc remelted. EFR, electroflux remelted. 

To achieve this step of the process, the product is heated at a temperature inferior to the lowest eutectic point to avoid any remelting, usually around —35°C, and the ice condenser is cooled down at a temperature well below the shelf temperature (usually —55°C) and dependent on the pressure (vacuum) level requested in the chamber. 

---