s.ali ebrahimian - dezful branch azad university
m ahmadi - amirkabir university

metallurgical welding joints are extensively used in the fabrication industry including ships offshore structures steel bridges and pressure vessels when welding a long butt-welded joint residual stresses and distortions can occur near the weld bead due to localized heating by the welding process and subsequent rapid cooling high residual stresses in regions near the weld may promote brittle fractures fatigue or stress corrosion cracking residual stresses in the base plate may reduce the bckling strength of the structure members the use of fracture mechanics enables a critical defect size in a structure to be specified at a given operating stress provided that the fracture toughness and yield properties of the material are known acoustic emission technique AET is widely used to characterise the deformation and fracture processes in materials .

welding ,acoustic emission,welding sequence,tensile test