The niobium in the alloy is the matrix, and the melting point of Nb is 2468℃, which is a refractory metal, so the alloy ingot is generally prepared by electron beam melting or the combination of electron beam and vacuum consumable arc melting for high purity requirements. The process of electron beam melting has high energy consumption, high cost, difficult to accurately control the alloy composition, and the ingot grain is coarse, the surface quality is poor, and it is easy to produce metallurgical defects such as shrinkage porosity, which brings inconvenience to the subsequent forging and other hot processing. Although the combination of electron beam and vacuum consumable melting solves the metallurgical defects of alloy ingot, it is difficult to accurately control the alloy composition, and the electron beam single furnace melting amount is small, which is not suitable for the production of industrial scale alloy ingot. Therefore, the preparation process which is suitable for industrial scale with high efficiency, low cost and satisfying the material uniformity has become a research hotspot.
Compared with the prior art, the invention has the following advantages: the invention only adopts the vacuum consumable arc melting method to prepare the niobium-zirconium alloy ingot, increases the melting current and greatly increases the melting voltage, so that the power is multiplied, and enough heat is generated to fully melt the high melting point metal niobium. Vacuum consumable melting can achieve good feeding effect, avoid the occurrence of segregation, porosity, shrinkage and other metallurgical defects, and provide good billet for subsequent hot processing and mechanical processing. The invention can not only realize the purpose of cleaning and homogenizing the ingot of niobium-zirconium alloy, but also control the deviation of longitudinal main element zirconium composition within 0.3%, and the vacuum consumable melting method has mature technology, high process automation, simple operation and low cost, and can realize the preparation of industrial scale ingot.
The vacuum consumable arc melting method was used to prepare the ingot of niobium-zirconium alloy. The melting current was increased and the melting voltage was greatly increased, so that the power was multiplied, and the high melting point metal niobium was fully melted with enough heat. The type of alloy is small, the arc stabilization current is properly reduced, and the energy consumption is reduced. Prolong the cooling time of the ingot, prevent the high temperature oxidation of zirconium and niobium alloy, and ensure the content of impurity elements in the ingot. The bottom pad is placed to prevent arc light from penetrating the bottom of the crucible in the early smelting stage. At the same time, the use of vacuum consumable melting can achieve good feeding effect, avoid segregation, porosity, shrinkage and other metallurgical defects, and provide good billet for subsequent hot processing and mechanical processing.
