Titanium alloy melting method
One of the topics of titanium alloy smelting is to put in place a new technology to eliminate the defects of various inclusions in the ingot obviously and ensure the chemical composition uniformity of the ingot. Conventional use of vacuum consumable arc melting, but not completely solves the mixed problem. In recent years, emerging furnace hearth melting methods, and to industrialization, there are two main methods:
1, the use of autonomous heating source semi-continuous hearth melting.
In this method, the solid charge is melted and the liquid on the route from the melting zone to the crystallizer remains liquid. The cold bed furnace effectively separates and removes the high specific gravity inclusion by the difference in specific gravity. It can be subdivided into plasma cooling bed furnace and electron beam cooling bed furnace.
It is most effective for removing low-density inclusion electron beam furnace. However, the obvious advantage of the plasma cooling bed furnace melting system is the fact that it can maintain different vapor pressure of the alloy components. During the melting process, there is no obvious loss of easily-evaporable elements such as Al, Cr, Mn and the like; meanwhile, the crystallization speed can be significantly reduced β stabilizing element completed to the liquid phase, which can prevent the formation of β-spot.
The United States General Electric engine with titanium on the use of this method has achieved significant results. In recent years, foreign countries, the cooling bed furnace smelting technology is to further improve the purity of the metal, to prevent aircraft engine titanium alloy compressor disc inclusion weaknesses an important means.
2, condensate shell electrode melting
This type of hearth smelting is marked by a large smelting current. It functions as a heart by a cold metal crucible, which continuously flows into the crucible and into the mold at the end of the smelting.
As the crust melting is a variant of the hearth melting, which has a high refining ability to remove impurities can be a variety of inclusion, the comprehensive melting effect and the first type of considerable.
The actual experience of a large number of ingots proved that there were a strong scouring and impurity removing ability in the skull melting. Under the standard operation, there was no such accident that the metal was scrapped due to the inclusion.
The two methods are all a matter of comparison. If the hearth melting is invoked as a means to fabricate a consumable electrode for subsequent vacuum consumable arc melting, the former has obvious advantages over the hearth furnace. In the case of the same refining impurity removal ability, the cost of preliminary preparation and the cost of metal processing of the crust melting is low; all the metals smelted prior to pouring into the ingot are all in the liquid state and have the potential to achieve high chemical homogeneity of the ingot , To ensure the uniformity and safety of the alloy.
