The process by which a metal changes from a liquid state to a solid state is called the solidification process of the metal. The solidification process of ingots includes the transfer of momentum, heat, and matter, the phase transition process of solid phase nucleation and crystal growth in liquid metals, and the formation process of ingot structure that occurs with the above processes.

The so-called ingot refers to the casting of molten metal into ingots that meet the required shape, size, composition, and quality. Generally, ingots should meet the following requirements:

① The shape and size of the ingot must meet the requirements of pressure processing, otherwise it will increase waste and corner waste;

② There should be no defects such as pores, shrinkage cavities, slag inclusions, cracks, or obvious segregation inside and outside the ingot, and the surface should be smooth and even;

③ The chemical composition of the ingot meets the requirements, the crystalline structure is basically uniform, and there are no obvious weak crystalline planes or extremely coarse grains.

Whether in Russia or other countries, the production of titanium alloy semi-finished products mainly involves first melting and casting cylindrical ingots, and then processing them into small diameter (100-150mm) semi-finished products or slabs through deformation. The diameter of industrial ingots weighing 2-10 tons mainly ranges from 570 to 850mm. The forming process is selected based on the principle of minimizing labor consumption during the production of semi-finished products and maximizing the use of ingot deformation equipment. The research results and extensive practical experience indicate that the mechanical properties of a series of titanium alloy semi-finished products processed from ingots of different diameters are the same at a fixed degree of deformation.

Because increasing the weight of the ingot will substantially increase the output of the melting furnace, the selection of ingots with larger weight z should be based on the technical feasibility of the equipment when formulating the process. The required quality of metal relies on the necessary degree of deformation, which ensures the required output of titanium alloy semi-finished products with minimal capital investment and labor consumption.

However, the increasing demand for metal quality and the complexity of alloy composition in melting have forced people to seek new methods to ensure efficient production of small-diameter cylindrical ingots and flat ingots, whose shapes and sizes are maximally suitable for the processing of semi-finished products.

The experiment of melting large-diameter electrode electroslag into small-diameter cylindrical ingots shows that due to the incomplete inertness of the flux, the quality of the obtained ingots is not as good as that of vacuum furnace melted ingots. In addition, the production capacity of the designed electric slag melting device is significantly lower than that of existing industrial scale vacuum arc furnaces for melting titanium alloy ingots. Therefore, choosing a reasonable ingot size and production method remains a research topic in the future.