Similar to other metals, the shrinkage behavior of titanium tube during casting also undergoes a change from liquid state to solid state and then to solid state. This shrinkage behavior is usually divided into volume shrinkage and line shrinkage. The volume shrinkage reflects the change of the entire volume during the casting process of the titanium tube. Since the total volume shrinkage is equal to the volume of the concentrated shrinkage cavity of the casting plus the volume of the shrinkage porosity, the solidification shrinkage behavior of the alloy casting process is related to the volume shrinkage of the alloy. The characteristics of shrinkage cavities and shrinkage porosity defects of drilled alloys are determined, which is of great significance for understanding the formation of shrinkage porosity and shrinkage defects of titanium tubes.
Important factors affecting the solidification shrinkage of titanium tubes include alloying elements, mold materials and mold structure. Since the alloying elements affect the crystallization temperature interval of the titanium tube, just like its effect on the fluidity, the solidification shrinkage of the titanium tube first depends on the characteristics of the added alloying elements, that is, the crystallization temperature formed between the titanium and the alloying elements. The size of the interval is related. The eutectic titanium tube with narrow crystallization temperature interval has good fluidity and is easy to form concentrated shrinkage holes, while the titanium tube with wide crystallization temperature interval has poor fluidity and is easy to form dispersive shrinkage holes, that is, shrinkage porosity.
Because titanium tube has a series of good physical properties, as an excellent structural material, it can compete with stainless steel and nickel alloy for application scope: in many sectors of the national economy, the use of titanium tube improves product life and improves The reliability and productivity of the equipment, the speeding up of the process, and the improvement of labor conditions, all of which have resulted in significant economic benefits.
