Development of Low Cost Near Net Shape Forgings from Ti 6-4 by Special Process Technology

摘要

Due to the high material and machining costs of titanium alloys, near net shape forming processes are attractive in order to reduce the component costs. Near net shape forgings can be produced by isothermal forging, but this leads to high die costs and a very low productivity due to the low strain rate which is necessary to reduce the flow stresses during the die forging. An economic alternative to the existing process is the β-forging process. In this case the flow stress is significantly reduced by heating the material above the β-transus, resulting in low forging forces and a good die filling behaviour. It allows the production of very thin walled and complex geometries with a reduction of material input weight of approx. 30 % compared to a conventional die forging, which also results in reduced machining cost. The paper will present the development of the β-forging process and the achievable properties and will give examples of actual production parts.