Mezoscopic mechanisms of deformation in welded connections extension of. structural steel

Mezo- and macrobands of the localized plastic deformation has an accommodation nature. Their orientation is of noncrystal character and is determined by the directions of maximum shear and normal stresses. . The type of band structures occurring in the region of the main metal depends directly on the scale of the voltage concentrates (type of the welded connection): heavy macroconcentrate (argon-arc joint) initiates the formation of macrobands over the scheme or abruption; weak macroconcentrate (electric beam joint) causes the appearance of the assemblage of the shear mezobands and abrupt macrobands. The values of the main plastic shear characterizing the deformation material state in the region of the hands formation are differed approximately by a factor two. . Two mechanisms of the welded connection destruction were discovered associated with the formation of shear macrobands in the area of the thermal effects and with the development of the accommodation processes of plastic flow relaxing the voltage macroconcentrate.