1. Luca Dassa – 09/06/2015 1 / 5 Galling SolutionAdvantagesDisadvantagesComments Silver / copper coatingSolidNot easy to do (neither at CERN neither outside) – very thin coating (3 um) PVD deposition could be an alternative IBE surface treatmentSolid457€ per set (≈2-5 € /bolt)Never tested. Should be suitable for UHV Dicronite dry lubricant“anti-galling” declared?Never used at CERN Molykote® 321 Dry Film Lubricant Spray Cheap, used in UHV devices for nuclear plan* Cryolab**, already used in tiny amount Solvent dispersion of MoS2, graphite and inorganic binder / Used in Linac 4 (at warm) Vacuum grease (Apiezon N) Used in all the cryostat devices (vacuum sealing, thermal coupling…) Used for sealing. To be tested Silicone oil + Inorganic thickener baseline * Reference A. Lafuente Mazuecos 1 2 3 ** Reference T. Koettig

2. Luca Dassa – 09/06/2015 2 / 5 SolutionAdvDisadvComments Serrated Belleville Washer in CuSn8 NASA References: looking effect Stiffness value unknown They combine spring effect + locking effect Standard Belleville washers in Ti with additional “machining” High costAsk for quotation Positive locking device (mechanical ) i.e. lock wire or tab washer Highly reliableComplexCould be too complicate to add Thread -> Spiralock (friction locking device) Good reference: used in nuclear plan*, used in space, already used in Ti4Al6V, suggested by NASA reference Test needed The only reference is the Not reliable with vibrations Cost for the tool (90 € per tool) Locking * Reference A. Lafuente Mazuecos baseline 1 2 3

3. Luca Dassa – 09/06/2015 3 / 5 Washers (1) Why? Do we really need a washer? Role of a washer: Locking effect Bearing surface function (Pressure under the screw) Spacer function Spring function (Preload regularization) Belleville or Grower have the same function if they are not flattened New offer for Grower washers: 1.52 € per washer (total for tests and dummy: 485 €) Warning: washers need to be fully compressed if we want that the FE models are reliable!!!

4. Luca Dassa – 09/06/2015 4 / 5 Washers (2) Schnorr: CuSn 8 (2.1030) - Tin bronze according to DIN EN 1654 http://www.schnorr.de/en/germany/products/materials/ Missed information: spring stiffness? Integrated thermal contraction (293K-4K): I assume pure Cu -> 0.324% (for pure Ti -> 0.151%) Assuming 1 mm thickness: (0.324%-0.151%)*1mm= 1.7 um

5. Luca Dassa – 09/06/2015 5 / 5 Ti Grade 6 bolts We have offer for pre-series. M6 12.25 € per bolt delivery time: 4.25 months