The technique allows to predict crack formation during heat treatment of welded joints. It has studied how chemical activism of flux influences and their mixtures on the properties of the weld metal at electroslag welding. It has been shown that increasing the chemical activity of the flux by increasing the silica content therein to 40% (mixture of fluxes ОФ-6 and AН-8) in the weld metal increases the proportion of readily deformable nonmetal oxide inclusions. This leads to an increase in the plastic properties and deformation capacity of the weld metal during welding stresses relaxation and eliminates the risk of a weld is executed electroslag welding reheat cracking.

Keywords: Welded joints, electroslag welding, chemical activism of flux, structure and mechanical properties, relaxation process of welding stresses, reheat cracking.