الفهرس 
FSW microstructure evolutionOnly 14 pages are availabe for public view
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Abstract
Steel sheets joining can be done by many welding techniques which have advantages and disadvantages. selection of one among them to fabricate specific structure is delicate and most of the time depends on theoretical and practical experience.
In this investigation the fracture mechanics science was used to study the behavior during fracture of joints made by different welding techniques.
Fracture resistance of low alloying element low carbon steel sheet welded joints had been evaluated by Essential Work of Fracture (EWF) testing method. Testing was done on DENT specimens which were prepared by EDM using 0.3 mm wire diameter.
More than thirty two notched specimens with different notch lengths had been tested and the Specific Essential Work of Fracture (we) was evaluated and interpreted by different models. The results were presented and analyzed to make evaluation and assessment processes. Also features of the fracture surface were evaluated using SEM microscopy for comparison as well as the energy consumption of the different welding processes.
The EWF gave results which are matched with the results of tension test, micro hardness test for as received material and all type of welds, also it gave matched results with the power consumption of the different weldments. The weldment of GTAW gave higher Essential Work for Fracture (higher fracture energy) if it is compared to that of FSW and GMAW.
The SEM micrographs for the fracture surface of the as received material, GTAW and FSW weldments tensile test specimens assure those fractures are mixed brittle ductile types but differ in their tendency for fracture while for GMAW the fracture type is ductile which in turn interpreting the tension test results and micro hardness results for weldments.
FSW has the lowest value of energy consumption to fulfill the welded joint if it is compared to GTAW and GMAW.