Keyword: «cold cracks»

The parameters of the welding technology that affect the resistance of welded joints to the formation of cold cracks are considered. The strength of their impact depends on the chemical composition of the main and welding materials, the geometry of the welded joint and the dimensions of the product. The first group of parameters evaluates the structural state, the second – the force and deformation conditions in the welded joint, the third – the level of hydrogen in the welded joint. The parameters characterizing the thermal welding cycle affect the indicators of all three groups and through them control the level of technological strength of the welded joint. The applicability of maximum local tensile stresses in the stress concentrator region has been experimentally shown to compare different test methods for the formation of cold cracks.

This paper demonstrates the feasibility and necessity of using the acoustic emission method for assessing the process strength of welded joints. The presented improvement of the methods allows real-time monitoring of the kinetics of the occurrence and development of cold cracks in welded joints of high-strength steels during delayed fracture, which undoubtedly improves the level of assessment of the technological strength of welded joints. Using the acoustic emission method, new criteria-based approaches to assessing the process strength of welded joints are proposed, based on appropriate processing of acoustic emission data.