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Characteristics of Titanium Alloy Forging Process

The quality of titanium alloy forgings is mainly determined by the forging process. Therefore, before working out the forging process, it is necessary to learn the characteristics of titanium alloy forging process, which mainly includes following three aspects:

1. High Deformation Resistance

The deformation resistance of Ti alloy is higher than that of Cr-Ni-Mo alloy at the same forging deformation temperature. It increases rapidly with the decrease of deformation temperature. Even when the deformation temperature falls slightly, the deformation resistance of titanium alloy will increase significantly. Thus, the top priority of titanium alloy forging is to select reasonable deformation temperature in forging process.

2. Poor Thermal Conductivity

With poor thermal conductivity, the surface of titanium alloy billet cools faster than the inner after heating. Improper operation will cause large temperature difference between inside and outside of the billet, aggravate the inhomogeneity of internal and external deformation of titanium alloy billets, and even lead to crack, which seriously affects the service life and quality of titanium alloy forgings. Therefore, it is crucial to fully preheat the tools that directly contact with titanium alloy blanks, such as forging dies and clamps.

3. High Viscosity and Poor Liquidity

This characteristic requires that the lubrication must be highlighted during forging deformation of titanium alloy. Otherwise, inverse flow and sticking die that sometimes tears forgings will occur. At the same time, the deformation resistance will be significantly enhanced due to the increase of friction. According to experimental research, the friction coefficient of titanium alloy is 0.5 without lubricant and 0.04-0.06 with glass lubricant. Hence, choice of appropriate lubricant plays an essential role in ensuring the quality of titanium alloy forgings.

Like other metal materials, high-quality titanium alloy parts need to be manufactured by forging process. The common forging processes include free forging, hot die forging and special forging.