@inproceedings{PetrovBokuchavaPapushkinetal., author = {Petrov, Peter and Bokuchava, Gizo and Papushkin, Igor and Genchev, Gancho Vladimirov and Doynov, Nikolay and Michailov, Vesselin and Ormanova, Maria}, title = {Neutron diffraction studies of laser welding residual stresses}, series = {19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 26-30 September 2016 Sozopol, Bulgaria}, booktitle = {19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 26-30 September 2016 Sozopol, Bulgaria}, publisher = {SPIE}, address = {Bellingham, Wash.}, isbn = {978-1-5106-0953-2}, doi = {10.1117/12.2261802}, language = {en} } @misc{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin and Bokuchava, Gizo and Petrov, Peter}, title = {Residual stresses formation in multi-pass weldment: A numerical and experimental study}, series = {Journal of Constructional Steel Research}, volume = {138}, journal = {Journal of Constructional Steel Research}, issn = {0143-974X}, doi = {10.1016/j.jcsr.2017.08.017}, pages = {633 -- 641}, abstract = {In this study, the residual stresses distribution induced by multi-pass arc welding of the steel S355J2+N are investigated experimentally and numerically. An extended approach is used for the simulations, which considers the change of the local microstructure properties due to multiple reheating. Experimental material data obtained from physical welding simulations with GleebleĀ® are used for the model calibration. The experimental stress study is performed using a neutron diffraction method on a fourier stress diffractometer. Numerical analysis of the welding stresses formation in the weldment is performed and compared to the experimental study. The results explain the influence of the welding thermal history on the resulting local thermo-mechanical properties in the heat-affected zone and, thus, on the residual stress distribution. The consideration of the local microstructure properties in the welding simulation leads to a significant increase in accuracy of the numerical results. The major influence factor on the residual stress formation is the change in the interpass microstructure yield strength. When a root pass with short cooling times is subjected to re-austenitisation in the fine-grained zone, the yield strength increases in this area and affects consequently the residual stress distribution. The influence of the reheating is detectable in the depth of the weldment, but it is less significant for the residual stress formation near the surface of the welded joint.}, language = {en} }