The electron beam melting and refining of titanium alloys

Electron beam technology has advanced considerably in the past decade and is now an acceptable industrial production technology for tonnage quantities of metals. The equipment required has been refined in design and can now be operated reliably for long periods. The furnace designs have also been improved to reduce down-time and maintenance problems, leading to a situation where the process cost compares favourably with the alternative techniques of melting and refining titanium alloys. It is postulated that the EBCHM process provides a very significant advantage in the removal of ‘hard-alpha’ defects and so is a superior route to the production of rotating-part alloys. The balance of the process parameters required for this aim, against the parameters required for alloy composition control are reviewed. It is evidently possible to maintain this balance in the industrial environment. It is concluded that the EBCHM process is presently the melting system of choice for high-quality alloys and that industrial expansion of this capability will take place in the near future as demand rises. The furnace design and operation necessary to make the quality required are now reasonably-well established and proven by the production of a large amount of alloy destined for engine and airframe use.