Effect of Local Combined Thermal Action on Value and Distribution of Residual Stresses in Steel 20 Plate

This work investigates the influence exerted by the combined thermal effects of aluminothermic welding and arc welding with solid wire on the residual stress in the plate material. A mathematical model is constructed based on the Prandtl-Reuss model, where Hooke’s law is substituted with the Duhamel- Neumann law. It is considered that the deformations are low. Irreversible deformations develop when the von Mises yield criterion is satisfied, which includes the Johnson-Cook strain hardening function. In order to determine the parameters of this function, a number of tensile tests are carried out on parent metal samples and welding material obtained by electric arc welding with solid section wire or by a combined method of aluminothermic welding. The thermal effects are modeled by a double comet- shaped ellipsoid proposed by Goldak. For the combined welding method, the additional thermal effects from the exothermic reaction of the aluminothermic filler material and the lower heat dissipation due to the formation of a slag crust are considered. By analyzing the residual stresses, it is concluded that the use of flux-cored wire with aluminothermic filler in automatic electric arc welding results in lower levels of residual stresses, thereby positively affecting the subsequent operation of the welded structure.