There are five methods of alloy casting for Nb-Ti superconducting alloy:
(1) with powder as raw material of true blank arc furnace melting casting method -- niobium and titanium powder as raw materials, according to the appropriate proportion of mixing, molded into electrode, after high temperature curing, welding after true blank arc furnace melting casting for two or more times, niobium titanium alloy ingot.
(2) True blank consumable arc furnace melting casting with strip or rod electrodes -- Niobium and titanium raw materials are respectively smelted and processed to make strips or rods. After they are prepared into electrodes, they are smelted twice or more in vacuum consumable arc furnace to get niobium titanium alloy ingots.
(3) The vacuum electron beam furnace and vacuum consumable arc furnace combined casting method -- the same method as above, niobium and titanium are respectively made into strips or rods, and prepared as electrodes. The niobium titanium alloy ingot is obtained by joint casting in vacuum electron beam furnace and true blank consumable arc furnace.
(4) vacuum electron beam furnace melting casting method with strip or rod preparation electrode -- niobium and titanium are respectively made into strip or rod, they are prepared as electrodes, in the vacuum electron beam furnace casting twice or more, niobium titanium alloy ingot.
(5) with high quality sponge titanium and niobium rods prepared electrode for the purification of electron beam is blank electricity arc furnace with true shell furnace smelting method, by the high quality sponge titanium compressed into rods, with the vacuum electron beam furnace melting mixture electrode, purification of niobium rods in true blank electricity arc furnace and shell furnace inside two kinds of furnace type, joint into niobium titanium alloy ingot casting.
The melting and casting method of Nb-Ti superconducting alloy mentioned above, using Nb-Ti and Nb-Ti powder as raw materials, has some advantages in preparing Nb-Ti alloy with high uniformity, but it is easy to cause more impurities in the gap, and the process is complicated.
Niobium titanium superconducting alloy ingots cast by vacuum electron beam furnace with niobium and titanium strips or rods as electrodes can obtain excellent plastic alloys with few impurities, especially those with little gap impurities. However, the fluctuation range of titanium content in niobium N alloy component is large.
The titanium content of niobium titanium alloy ingot cast in vacuum consumable arc furnace fluctuates within ± 1.5%. The fluctuation range of vacuum electron beam furnace casting is ± 3% or a little more.
