Effect Of Discontinuites, Repair Welding, Crack Arrest Methods On Fatigue of Longitudinal Butt Welds in Aluminun 5456 Plate

Author:  Nordmark, Herbein, Grimm, Dickerson
Source:  No. DTNSRDC/SME CF-23-84
Doc ID:  1985007
Year of Publication:  1985
Abstract:  
The effects of discontinuities, repair welding, and crack arrest methods on the fatigue performance of longitudinal butt welds in 1/4 in. thick aluminum alloy 5456-H116 have been investigated. This work is a follow-up to earlier work on sound welds and to a similar investigation on transverse butt welds. The lack of penetration and gross porosity discontinuities introduced into these welds did not affect the fatigue strength of the reinforcement intact welds. Repair of the discontinuities reduced the fatigue life by 40 to 75 percent. The fatigue strength of repaired welds was restored by brush peening. Crack arrest methods included repair welding and interference bolts in drilled 0.28 in. diameter stop holes. The insertion of the interference fit bolts arrested the cracks and produced lives equivalent to those of sound welds. Much less benefit was obtained by using the reinforcement intact repair welds to stop cracks. Recommendations are made for the repair of transverse and longitudinal butt welds. Distribution authorized to U.S. Government Agencies only; Test and Evaluation; September 1985. Other requests for this document shall be referred to the Naval Sea Systems Command (SEA 05r). Washington DC 20362. Prepared for Daved W. Taylor Naval Ship Center, Bethesda, Maryland 20084