Case Study 1

Improved Material Yield, Reduced production Time

Background
Inconel 718 is a high Nickel (50-55%) based alloy. It combines corrosion resistance and high strength with outstanding weldability including resistance to postweld cracking. Used in gas turbines, rocket motors, spacecraft, nuclear reactors, pumps, and tooling Inconel 718 has excellent creep-rupture strength at temperatures to 1300F.

The rising cost of Nickel was having a significant impact on the price of Inconel 718. To counter this cost increase pressure a major aeroengine builder turned to Metal Spinners Group to re-engineer a conical pressure seal in one of its engines, from a forging based component to one produced from a spinning. The overall aim being to reduce cost via improved material yield, reduced machining time and with less environmental impact through more efficient processing and reduced production lead-times.

Challenge
The seal is a performance critical component within the engine being approximately 30" in diameter and 5/8" at its thickest portion. The component was manufactured from a hot forged Inconel 718 blank from which the final component was machined. In order to machine the final profile a forging blank of approximately 2.5" thick was required. The vast majority of this forging was being machined away. This process resulted in high input material costs; extensive machining requirements; excessive turned swarf; and extended lead-times.

Solution
Metal Spinners Group's proposal was to spin a near net shape envelope manufactured from standard three quarter inch thick plate material from which the final component could be machined. As a near net shape, the spun envelope  reduced the material content from that required in the current forged pre-form. Using three quarter inch thick plate reduced the input material content and cost significantly from that of that of the 2.5" thick forged ring. 

The 2.5" forged blank machining requirements were substantial requiring a series of "rough cuts" prior to the final machining operations. The spun near net shape significantly reduced the machining requirement by eliminating the rough machining requirement of the forged route. The inherent stability of the spinning, plus the ability to undertake several machining operations in situ on the spinning lathe, also provided improved repeatability of the final machined component.

Results
The spinning route provided additional benefits in terms of inventory control and component availability. The use of standard materials and reduced machining times allowed a reduction in raw materials and WIP within the supply chain. The spinning route reduced the lead-time over that of the forged route allowing a greater flexibility to match production schedule requirements at an earlier stage.

Metal Spinners Group's ability to develop and machine near net shape envelopes manufactured from plate material has been successfully transferred into other performance critical applications including Medical MRI Scanners, Military Fighting Vehicles and Offshore Oil applications.

 Original 2 1/2 inch thick blank

 Spun 3/4 inch preform

 Machined engine seal rim

Cross section showing material savings