The effect of upsetting conditions on flash weld toughness. Study on toughness improvement of flash welded joints in high strength steel

Abstract

An investigation was carried out of the factors influencing the toughness of flash welded high strength steel plate.¹ It was explained that the major factors for toughness degradation can be summarised by the following: there is an inclusion factor, that is oxides which remain at the weld interface and act as the starting point for fracture and the inclusions within steel which tend to be parallel to the weld interface due to metal flow; there is a microstructural factor, that is degradation of the microstructure due to coarsening of former g grains, a localised softened layer at the weld zone centre and the texture formed where there has been heavy rolling. Consequently, in order to secure toughness, a reduction of oxides at the weld interface and an improvement of steel material purity are required for the former case and the post weld heat treatment is required for the latter.