The influence of casting technology on titanium castings

The influence of runner on casting integrity

Due to the poor casting performance of titanium, the runner setting of titanium investment mold is particularly important. If the runner is vertical by casting cobalt chromium alloy and stainless steel, incomplete casting will often occur. The runner of titanium investment mold has the following requirements:

The diameter of the casting path shall be thick (not less than 4mm) and short to ensure that there is enough titanium liquid to inject into the casting cavity through the shortest way; The connection between the runner and the investment mold shall be properly thickened; The number of casting tracks shall be 3-4; Parallel interpolation or lateral interpolation can be used; Avoid forming right angles. Effect of temperature of secondary mold on surface properties of titanium castings

The contamination of titanium liquid by the embedded material is not only related to the vacuum degree of the melting casting chamber and the composition of the embedded material, but also related to the mold temperature. When the mold temperature is high, the titanium liquid is easy to react with the embedded material, and Zr, Al, Si and other elements can easily diffuse into the titanium matrix to become interstitial elements, forming a thicker hardening layer, thus increasing the tensile strength and yield strength of the casting, reducing the ductility and increasing the brittleness. The increase of oxygen content has the most obvious effect on the mechanical properties of castings. When the mold temperature is low, the hardened layer also becomes thin. However, low mold temperature will affect the casting flow rate, so the mold temperature should be properly selected, sometimes according to different purposes to determine the mold temperature.