RESEARCH DEVELOPMENT AND TEST OF REFRACTORY METAL ALLOY FASTENERS.
Rept. for 25 Apr 61-15 May 64,
REPUBLIC AVIATION CORP FARMINGDALE N Y
Pagination or Media Count:
The problem of producing and using standard fasteners metallic for use to 3000 F was investigated. The final production phase consisted of one molybdenum alloy, TZM, and one columbium alloy, Cb752, with the threaded fasteners incorporating a special thread form. The Pfaudler PFR-6 coating was used on the molybdenum alloys while the Tapco Cr-Ti-Si coating was used on the columbium alloys. Final approved fastener configurations for both alloys included common rivets brazier head, Hi-shear rivets flush head, flush head screws, hexagon head bolts, and nuts for use with the threaded fasteners. Blind fasteners were produced from columbium alloys only. Tensile and shear data are presented encompassing the temperature range -320 through 3000 F. Ambient and elevated temperature fatigue and joint test data are also presented. The program has shown that usable fastener configurations can be manufactured from molybdenum and columbium alloys, and that the resultant items can be successfully coated for satisfactory oxidation protection at nominal utilization temperatures. Extremely large reductions in load carrying capability at ambient temperatures were experienced in the molybdenum alloys after coating. This phenomenon was not as serious in the columbium alloys. Author