The method of vacuum plasma welding is used to prevent the influence of external atmosphere on the oxidation of electrodes when welding consumable electrode.
The NbTaHf alloy billet adopts electron beam melting (EB). In the melting process, the vacuum degree, gas leakage rate, melting current and melting voltage are strictly controlled, the pores in the billet are eliminated, the impurities in the alloy low melting point are removed, the local enrichment area of tantalum and hafnium elements is eliminated, the microscopic composition uniformity of the intermediate alloy ingot is improved, and the risk of tantalum non-melting is eliminated. Ensure the uniformity of alloy composition.
NbTaHf alloy adopts vacuum consumable arc melting (VAR). During the melting process, the vacuum degree, gas leakage rate, melting current and melting voltage are strictly controlled to improve the ingot composition uniformity, reduce the impurity content, and reduce the grain size in the alloy ingot. The finished product is replenished in the later smelting period, and the current is reduced step by step in the replenishing stage to achieve continuous reduction in the depth of the melting pool. Finally, a shallow molten pool is obtained before the arc break to ensure the stability of the melting process and improve the composition uniformity of NbTaHf alloy ingot, so as to prepare the ingot meeting the design requirements.
In addition to Nb metal Ta metal and Hf metal ingot preparation process from scratch, the smelting ingot specification range is wide, the ingot horizontal and longitudinal composition uniformity is good, the yield is high, there is no tantalum and no frit, and the NbTaHf alloy ingot continuous production is realized. It lays a solid foundation for the introduction of Ta and Hf by NbTaHf alloy in the preparation of Nb3Sn wire.
