INFLUENCE OF POST WELD TREATMENTS ON THE FATIGUE BEHAVIOR OF AL-ALLOYWELDED-JOINTS

In this paper the influence of different post welding treatments, such as ageing or shot peening, on the fatigue behaviour of Al-alloy welde d joints was investigated. The analysed joints were candidates for car structural applications. Several four point bending fatigue tests wer e conducted on GMAW specimens subjected to different post weld treatme nts. The residual stress field acting on specimens was measured by the X-ray diffraction (XRD) technique. The results of tests were discusse d with the aid of a finite element model of the specimen aimed to calc ulate the actual fatigue cycle, also taking account of residual stress es and of their redistribution during the test. This allowed to charac terize the fatigue resistance of the joints, taking account of the eff ective stress acting in the region of crack initiation. (C) 1998 Elsev ier Science Ltd. All rights reserved.