Development Of Disc Forgings In Ti-6Al-4V Alloy For Aero-engine Application

Discs are very critical rotating components in aero gas turbine engines and are subjected to high stress and temperature during service. In order to meet the severe operational conditions, disc forgings should possess fine and homogenous microstructure and isotropic properties. This calls for extremely close control of processing and heat treatment procedures. The discs are also subjected to extensive testing and evaluation to the stringent specification in view of its critical end use. Thus, the indigenous development of disc forgings in Ti-6Al-4V for the first time in India was a major technological challenge. To establish indigenous capability for production of critical components, the largest fan disc [Drg. No. : KB-010F - Disc stage III fan forging] of Kaveri engine in GTM-Ti-64 material [Ti-6Al-4V] was taken up using the high energy forging equipment of Bharat Forgings Limited, Pune. This paper presents the details related to the processing, structure and property evaluation of discs made of different forging stocks and important technical observations during the developmental exercise.