Evaluation of Isothermal Forgings for T53 Impellers.

摘要

The primary objective of this program was to evaluate isothermal forgings of Ti-6Al-4V alloy in the form of near-net shaped T53 impellers and determine their potential technical and economic advantages over conventional forgings. An evaluation of mechanical properties showed the isothermal forging properties to meet current forging specifications. Finish machining of one forging was conducted using the current production process. This revealed a time saving of 2.1 standard hours over the conventional forging, a savings primarily in rough machining. Partially formed vanes are not realized as an advantage by the current milling process due to the cam controlled action of the cutter in the existing machining facility, i.e. several Gorton milling machines. A cost analysis of alternative vane milling methods, i.e. numerical and/or adaptive control, has led to the conclusion that a process modification would not be cost effective due to current high efficiency of the Gorton mill. It is therefore recommended that it a partial vane contour be included in the forged shape only to the extent that is effective in reducing input material cost without increasing forging costs. (Author)