Residual stresses in dissimilar welding

What is it about?

Residual stresses are investigated in an aluminum / steel welded joint using neutron diffection technique. A small step neutron diffraction scan was initially performed to determine the weld interface position along the measured transverse cross section. The small step scan enables to identify the wavy nature of the interface, which has been subsequently combined in the residual stress calculation. The resultant of all three components of the residual stresses is almost zero along the mid-thickness of the steel plate, validating the estimated stresses. Near the interface, residual stresses on the steel reveal an “M” shape distribution while in the aluminum sheet they show a “W” shape. The interfacial residual stresses in the steel originate from the thermomechanical processing condition, phase transformation and the mismatch in the coefficients of thermal expansion (CTE). At the vicinity of the interface, the aluminum plate presents a distribution of residual stresses similar to a superposition of residual stresses resulting from an arc welding and the effect of mismatch in CTE.

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Why is it important?

Residual stresses are important to be estimated in welded joints, there are almost no study available on residual stresses in the subject of dissimilar joints. Therefore this study is very important to provide innovative step to measure residual stresses in dissimilar welded joints.

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