Welding with a defocused laser beam

The results of experiments carried out to investigate the welding of austenitic stainless steels using a defocused laser beam are presented. It was assumed that the application of the defocused laser beam would increase the volume of the weld pool, which in turn would reduce the requirements on the preparation of edges and the gap between the workpieces. Microhardness was measured, 2D-computer tomography carried out, specimens were examined by metallographic techniques and the phase components of different zones of the weld pool were analysed by quantitative methods. Special features of the formation of the weld pool dependent upon the welding conditions were investigated. The results indicate that the application of the defocused beam produces high-quality welded joints and the method has also a positive effect on the stability of the vapour–gas channel and the phase composition of the weld metal. © 2016 Informa UK Limited, trading as Taylor & Francis Group.