Welding and environmental test condition effect in weldability and strength of Al alloy

The commercially available gas mixtures should be considered in terms of their suitability for ensuring arc and metal transfer stability, performance, and weld quality. The objective of the present paper is to study the toughness of Al5083-O aluminum alloy, to evaluate the variation of welding zone toughness as a function of the shielding gas composition and the testing temperature. To achieve these objectives, gas metal arc welding was performed with four different shielding gas compositions, and tests were carried out at four different temperatures. The welding zone was divided into four sub-zones for analysis, namely, weld metal, fusion line, heat affected zone and base metal according to the artificial notch positions. The suitability of a mechanical or structural component for specific service involving cyclic application of loads and thermal condition is determined by the use of the fatigue module. The software and fatigue module, COSMOSM and FSTAR, provides engineers with the capability to perform fatigue analysis of their structural designs using the database created with the stress module. Analysis can be performed easily and quickly to determine the predicted life of a design and identify areas that are fatigue critical. The solution is based on the Miner's rule approach and the ASME Boiler and Pressure Vessel Code. There is also a capability to evaluate the fatigue usage factor using the ASME Code for a simplified elastic-plastic formulation. Tensile and yield strengths did not have a great effect on tested temperature at +25 degrees C to -85 degrees C, but increased much at -196 degrees C. Also, strain tended to increase as test temperature decreased. Shielding gas composition dose not have a great influence on mechanical properties. The absorbed energy of weld metal-notched specimens did not depend on test temperature and mixing shield gas. On the other hand, the other specimens showed that as temperature was lower, absorption energy increased slightly up to -85 degrees C but the energy decreased so much at -196 degrees C. There is about 4.25% deviation between fatigue life analysis result and experimental result. (c) 2005 Elsevier B.V. All rights reserved.