Accession Number : ADA076197


Title :   US/Australia Collaborative Research Project on Corrosion Fatigue in D6AC Steel Joints


Descriptive Note : Final rept. Jan 1974-Aug 1978


Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH


Personal Author(s) : Harmsworth, C L ; Kemsley, D S ; Finney, J M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a076197.pdf


Report Date : Dec 1978


Pagination or Media Count : 112


Abstract : A U.S./Australian Program has been conducted to determine the effect of manufacturing-induced and environmental corrosion on D6AC steel Taper-Lok bolted joints as used in the F-111 aircraft. Under constant amplitude, traces of distilled water or concentrated hydrochloric acid in the bolt holes did not reduce fatigue life. Under spectrum loading traces of water did not affect fatigue life but traces of hydrochloric acid reduced the mean fatigue life of the joint by a factor of 110. The results of further constant amplitude tests and a limited series of spectrum tests confirmed previous findings that the life of those original joints in the F-111 which were manufactured using a six-flute hand reamer could be appreciably extended by rework with an 18-flute tapered reamer as used in later F-111 production. Other rework procedures involving cold working of the hole by a mandrel or specially designed fasteners showed little improvement when used in this relatively high-strength steel joint material. The effects of improved sealants and the capability of ultrasonic and magnetic NDI techniques for inspection of cracks at fastener holes were also investigated. It is concluded that the life of uncontaminated, properly fabricated and sealed D6AC steel joints as used in the F-111 wing carry through should not be a source of fatigue failure during a normal aircraft lifetime.


Descriptors :   *JOINTS , *FATIGUE(MECHANICS) , *CORROSION , *STEEL , FATIGUE LIFE , LOADS(FORCES) , HOLES(OPENINGS) , INSPECTION , ENVIRONMENTAL TESTS , AUSTRALIA , FASTENINGS , HYDROCHLORIC ACID , NONDESTRUCTIVE TESTING , MANUFACTURING , COLD WORKING , FIGHTER AIRCRAFT , UNITED STATES GOVERNMENT


Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy
      Mechanics
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE