Sintering furnace: titanium alloy casting process characteristics
casting
The shape and size of the piece, the second is to make the microstructure and performance of the casting meet the requirements of the design technical indicators. That is to say, the poor microstructure of titanium alloy formed during casting deformation is difficult to improve. Therefore, before developing the casting process, it is necessary to understand the casting process characteristics of titanium alloy. The casting process characteristics of titanium alloy mainly include the following three aspects
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1. Large deformation resistance
High deformation resistance is one of the prominent characteristics of titanium alloy casting deformation. Compared with other alloy structural steels, the deformation resistance of titanium alloy is large under the same casting deformation temperature, and increases rapidly with the decrease of casting deformation temperature. Therefore, due to the large deformation resistance of titanium alloy, the temperature of titanium alloy is slightly reduced during casting deformation, which will also lead to a significant increase in deformation resistance. Therefore, choosing a reasonable casting deformation temperature is the primary task of titanium alloy casting.
2. Poor thermal conductivity
Poor thermal conductivity is another significant feature of titanium alloys, and some titanium alloys have thermal conductivity. Poor thermal conductivity makes the surface cooling of titanium alloy billet after heating is faster than the inside. If improper operation will cause a relatively large temperature difference inside and outside the billet, aggravate the uneven deformation of titanium alloy inside and outside the billet during the casting deformation process, which will seriously affect the service life and service reliability of titanium alloy castings. Therefore, fully preheating tools in direct contact with titanium alloy billet, such as casting molds and clamps, is a very important work in titanium alloy casting production.
Due to the large viscosity and poor fluidity of titanium alloy, it is required that the lubrication of titanium alloy casting deformation must be strengthened, otherwise the phenomenon of viscous mold and material reflux will occur, and the deformation resistance will be significantly increased due to the increase of friction, and sometimes the casting will be torn because of the viscous mold. The experimental results show that the friction coefficient of titanium alloy upsetting at high temperature is 0.5 when no lubricant is used, and that of titanium alloy upsetting at high temperature is 0.04~0.06 when glass lubricant is used. Therefore, the use of reasonable lubricants in titanium alloy casting is an important measure to ensure the quality of titanium alloy casting.