Key points are not available for this paper at this time.
For the first time, complex hydraulic studies of pipes welded according to three different schemes were carried out, which made it possible to combine pipes of different viscosities, which affects the performance of welding joints. It was found that in the experimental temperature range, the zone of thermal influence of the second welding variant has the greatest resistance to the initiation of fractures under shock loading, and the lowest - the first variant. The static strength and ductility of the welded pipe joints of the second and third pipe welding options are approximately equivalent, and the resistance to the initiation of the thermally affected zone in all options is almost the same and not lower than that of the base metal. The results of the performed experimental studies indicate a weak correlation in the area of small values of impact viscosity with the characteristics of resistance to fracture propagation of welding joints in the conditions of full-scale pipe tests. The characteristics obtained from tests of full-thickness DWTT specimens are closer than the Charpy specimens to the actual performance characteristics of the weld joints in the pipe. In particular, it was established that the values of Az (-150C)=0.75 kJ and Ar (-150C)=0.45 kJ provide satisfactory resistance to the initiation and propagation of fractures in welding joints (at the base metal level). These characteristics correspond to KSU-60 = 0.5 MJ/m2, which is close to the impact toughness requirements for the base metal (0.55 MJ/m2). The use of optimal structural materials, that is, materials with high resistance to hydrogen destruction of both the base metal and zones of welding joints subjected to a thermo-deformation cycle of welding. A significant effect can be achieved by technological measures that will reduce residual welding stresses, as well as significantly reduce stress concentrators due to structural improvement of the shape of the welding unit. Application of such heat treatment regimes that restore the stability of metal with a coarse-grained and defective structure. Use improved pipe steels and welding materials, such as 06G2BAand 08 KhMCHA steels, which are characterized by increased resistance to hydrogen embrittlement and high crack resistance in aggressive environments, for the construction of pipelines of responsible purpose.
Макаренко et al. (Wed,) studied this question.