Ti-17 Alloy Isothermal Forging Process Parameters Optimization

Ti-17 can be classified as a "beta-rich" alpha-beta alloy, because it has 8% content of beta-stabilizer (Mo + Cr). Isothermal forging techniques are important commercial method for fabrication of Ti-17 rotating turbine engine disks to reduce final less machining and improve final microstructure and property uniformity of component through control of forging process condition. The effects of original state of material, preceding treatment, heat processing technique and forging process parameters on final microstructure and properties of isothermal forgings of the Ti-17 alloy are researched in this paper. Examination shows that grain size of the original material and processing technique have taken an important role in microstructure and properties of isothermal forgings of the Ti-17 alloy. With coarse grain in initial billet, it is necessary to add free-forging for getting a fine microstructure and excellent properties after isothermal forging. Optimum process is that the billet is upset and drawn many times with heavy deform in β region and (α + β ) region and cooled in air before isothermal forging.