NCSX

Initial Results from Friction Material Testing

January 29, 2007

NCSX

January 29,2007 2

NCSX

Testing Setup

• A traditional tension/compression testing machine has been configure to pull “double shear” combinations.

• Side rams allow the application of normal (transverse) loads

January 29,2007 3

NCSX

Typical Test Combination

• A 0.38” thick x 1.00” wide center element receives the application of friction-encouraging medium (if any)

• Wider (1.50”) side plates are added to each side of the center element with an axial overlap of 1.0”

• The normal/transverse load (10 kip max) is added at the center of the overlap areas (2 in**2 total area)

January 29,2007 4

NCSXTest Observations

• File 070129Summary.xls lists the outcomes of 21 trials– G-10 on SS (ambient,1 trial) m=0.18– SS on SS (amb/cold, 4 trials) m=0.21-0.26– SS/diamond/SS (amb/cold, 16 trials) mavg=0.53

• Many combinations

• The fundamental failure in the diamond-assisted trials was the tearing of the seated diamonds along/through the surface of the stainless– The tear-outs look like aerial views of perfectly plowed fields– This may be the functional limit of the material

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NCSXDesirability/Negatives

• The machine assembly personnel will probably find the 100/120 grit diamond (6 mil) on each side of the final shims to be the easiest to cope with during precision assembly.

• The 0.004 shim stock with diamond approach would allow last-minute changes in shim thicknesses – No lag time for off-site processing after shims are sized

– Assembly personnel would have bigger uncertainties with 4x12mil vs. 2x6mil when getting things “in tolerance”

• The nickel-bound diamond show NO degradation after failure– Relative mag perm 1.7<mrel<1.9

– Good cycle test candidate?

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NCSXNext Steps

• EKAgrip-Ceradyne (plant in Germany, US office in Michigan) is applying diamond to 0.004 SS shim as a parallel test to complement our current Braziler-supplier shims.

• NCSX will pick a relevant pressure range and produce a plot (pressure vs. m) for one or two selected front runners.

• Stellaloy – will the manganese improve things?• Cycle testing at 80K