Beveling selection for filled welds with constructive faulty fusion

Regarding welded constructions, not only their strength is of interest, but also saving of the weld metal consumption. For the latter, constructive faulty fusion of the joint can be used. But such joints suffer from stress concentration at the faulty fusion tip. When high-strength steels are used, this may lead to brittle or quasi-brittle failure, even under low loads. To raise the failure resistance power of fillet welded high-strength steels with the constructive faulty fusion, it is suggested to use a composite weld, where the root pass is made with a ductile (soft) welding rod and the rest of the passes with a high-strength (hard) one. Results of the study of stress-strain state and fracture resistance of mechanically heterogeneous fillet joints are presented, and the effects of fillet's bevelling geometry and ratio of mechanical properties of the hard and the soft weld rod metal are analyzed. The stress-strain state was studied using finite element method (FEM). FEM calculations and experiments with real weld joints demonstrate that the joint strength may be raised and expensive austenitic weld rods may be saved at the same time if composite joints are used in making fillet weld joints of high-strength steels with constructive faulty fusion.