Properties of welded joints of metal structures after hardening deformation-heat treatment

Abstract

The influence of deformation-heat treatment of welded joints from separate heating and using welding heat on the structure and properties of low-carbon steels for metal structures is considered in the paper. Some results of our research in this field are given. The main purpose of the research is to study the influence of the temperature gradient during welding and chemical composition of the structure formation in the basic and the weld metal, the possibilities of using welding heat for hardening welded joints of metal structures. Using technology for deformation-heat hardening of welded metal structures using welding heat will allow to reduce energy and labor expenditures, their manufacturing duration and increase the working efficiency on average by 1.2 times. The positive influence of deformation on forming an equilibrium structure in both the welded seam, and the heat-affected zone depending on the chemical composition of the weld metal is shown in the paper. The effect of carbon equivalent on the mechanical properties of welded joints is demonstrated. The research results can be used in manufacturing butt-welded joints of different designs, in particular pipelines at construction sites and plants. Using the obtained results will allow to improve the toughness of metal structures while maintaining sufficient hardness.