Titanium tubes are similar to other metals. During the casting process, their shrinkage behavior undergoes a transformation from liquid to solid and then to a solid state. Generally, we divide this titanium tube shrinkage into two types: volume shrinkage and linear shrinkage.
Volume shrinkage can intuitively reflect the volume change of titanium tube shrinkage during the entire casting process. Since the total volume shrinkage is equal to the sum of the volume of the concentrated shrinkage cavities and the shrinkage volume of the casting, the solidification shrinkage behavior of the titanium alloy casting process is closely related to the volume shrinkage of the alloy. This correlation determines the characteristics of shrinkage cavities and shrinkage defects in titanium alloys, which is of vital importance for a deep understanding of the formation mechanism of shrinkage cavities and shrinkage defects in titanium tubes.
Many factors affect the solidification of titanium tube shrinkage, among which alloying elements, casting materials and casting structures are key factors. Alloying elements will affect the crystallization temperature interval of titanium tubes, just as they affect fluidity. The solidification shrinkage of titanium tubes depends first on the characteristics of the added alloying elements, specifically, it is closely related to the size of the crystallization temperature interval formed between titanium and alloying elements. Eutectic titanium tubes with narrow crystallization temperature intervals have good fluidity and are prone to forming concentrated shrinkage cavities during solidification; while titanium tubes with wide crystallization temperature intervals have poor fluidity and are more likely to form dispersed shrinkage cavities, that is, shrinkage.
In addition to the titanium tube shrinkage and its influencing factors, titanium tubes also have a series of excellent physical properties, which make them an extremely outstanding structural material. Titanium tubes can compete with stainless steel and nickel alloys in terms of application range. In many sectors of the national economy, the use of titanium tubes has extended the service life of products, significantly improved the reliability and productivity of equipment, accelerated the process, and improved working conditions. All these positive changes have brought significant economic benefits.
