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Monday, May 15, 2006 - 3:30 PM
TALLT061.4

Electron-Beam Cold Hearth Melting for Ti-6Al-4V (ELI) Plate Materials

T. F. Soran, E. J. Haas, ATI Allvac, Richland, WA; T. Bayha, ATI Allvac, Monroe, NC

As a part of the Air Force Research Laboratory-sponsored Metals Affordability Initiative (MAI) Consortium program, Ti-6Al-4V ELI alloy plate products were manufactured from single melt, electron beam cold hearth melted (EBCHM) slab ingots.  The main objective of the program is to achieve significant cost savings for the EBCHM single melt slab product compared to the standard double VAR round ingot processing route.  Reduced production cost results from the use of less costly input raw materials, higher melt rates, fewer melt and hot work process steps, and improved yields compared to the standard double VAR processing route.  Melting large quantities of Ti-6Al-4V alloy in an EBCHM furnace presents challenges.  High vapor pressure elements such as Al vaporize preferentially from the molten pool in the high vacuum of EB furnaces.  The vaporization loss is a function of a number of variables including raw material makeup, raw material feed method, gun performance, melt rate, as well as hearth and casting surface area.  Control of Al in the final product involves the use of a number of tools including raw material chemistry control, mathematical modeling, feedback controls and operator experience.  Raw material must be chemically homogenous in order to have consistent chemistry in the final product.  The MAI program has previously demonstrated that the EBCHM process can produce standard grade Ti-6Al-4V ingots with both chemical homogeneity and resultant mechanical properties that are equivalent to current, double vacuum arc remelted (VAR) ingots.  AMS 6945 was published for standard Ti-6Al-4V flat-roll products.  ATI Allvac Standard plate processes have been applied for manufacture of beta-annealed Ti-6Al-4V (ELI) plate products up to 3” thick, and both static and dynamic mechanical test data have been generated.  A summary of the microstructure and rolled plate test data will be presented.


Summary: As a part of the Air Force Research Laboratory-sponsored Metals Affordability Initiative (MAI) Consortium program, Ti-6Al-4V ELI alloy plate products were manufactured from single melt, electron beam cold hearth melted (EBCHM) slab ingots. The main objective of the program is to achieve significant cost savings for the EBCHM single melt slab product compared to the standard double VAR round ingot processing route. A summary of the microstructure and rolled plate test data will be presented.