PSI - Issue 16

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

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Procedia Structural Integrity 16 (2019) 89–96 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” Effect of the structure on the mechanical properties and cracking resistance of welded joints of low-alloyed high-strength steels Olena Berdnikova*, Valery Pozniakov, Artemii Bernatskyi, Tetiana Alekseienko, Volodymyr Sydorets E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, 11, Kazymyr Malevich St., Kyiv, 03150, Ukraine Low-alloyed high-strength steels are widely used for the manufacture of welded metal structures in various branches of modern industry, including construction, agricultural, transport, engineering and defence. To produce joints of these metals mechanized or automatic welding in shielding gases are mostly used. Nowadays, such progressive technologies as laser and hybrid laser-arc welding implement, which allows obtaining welded joints at increased speed with much smaller dimensions of welds and heat affected zones, to improve the quality of high-strength steel joints and the to raise productivity of their manufacture. In this work, we studied the influence of the structural-phase composition and specific parameters of the structure, which are formed in the weld metal and the heat-affected zone, on the strength and crack resistance of welded joints of low-alloyed high-strength steels. The structure and phase composition of welded joints of high-strength steels was investigated depending on the technological parameters of arc, laser and hybrid laser-arc welding. It is shown how the microstructure affects the operation properties of welded joints. The relationship between the phase composition, the parameters of the grain and fine structure of the metal (substructures, dislocation densities, sizes and distribution of carbides in the structural components of bainite, martensite, etc.) of welded joints, their mechanical properties, fracture toughness and the level of local internal stresses in various structural components is investigated. The most influencing structural factors shown to be the dispersion of the bainitic structure and substructure, the uniform distribution of the density of dislocations, and the absence of extended dislocation cluster s − zones of nucleation and propagation of cracks. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 6th Interna ional Conference “Fracture M chanics of Materials and Structural Integrity” Effect of the structure on the mechanical properties and cracking resistance of welded joints of low-alloyed high-strength steels lena Be dnikova*, Valery Pozni kov, Artemii Bernatsk i, Tetiana Alekseien o, Volodymyr Sydorets E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, 11, Kazymyr Malevich St., Kyiv, 03150, Ukraine Abstract Low-alloyed high-strengt steels are w dely us for the m nufactur of w lded metal structur s in various branches of mod rn industry, including construction, gricultural, transport, ngineering and defenc . T produce joints of these metals mechanized or automatic welding in shielding gases re mostly used. N w days, such rogressive technologies as laser and hyb id laser-arc ing implement, which allows btaining welded joints at increa ed sp ed ith much smaller dimensions of welds and h at aff cted zon s, to improve the quality high-strength steel joint a d e o raise productivity of their manufactur . In this work, we studied the influence of t e structural phase composition and specific parameters of th stru ure, which are fo m d n the metal and t h at-affected zone, on t strength and crack resistance of welded joints of low-alloyed high-strength ste ls. The tr t r and ph se compos tion of wel ed joints f high-strength st els was investigated depend g on the technological parameters of arc, laser and hybrid laser-arc welding. It is show how the microstructure affects the operation prope ties of welded joints. The relationship between th phase composition, the parameters of the grain a d ine structure of the metal (substructures, dislocation densities, sizes an di tribution of carbides in structural compon nts of bainite, mar n ite, etc.) weld d joints, their mechani al properties, fracture toughness and the level of local internal stresses in various structural components is investigated. The most influencing structural factors shown to be the dispersion of the bainitic structure and substructur , the uniform distribution of th density of dislocations, and the absence of extended dislocation cluster s − zones of nucleation and propagation of cracks. © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. Abstract

* Corresponding author. Tel.: +38-044-205-2563. E-mail address: omberdnikova@gmail.com

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers 2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer- review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers * Corresponding author. Tel.: +38-044-205-2563. E ma l address: omberd ikova@gmail.com

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the 6th International Conference “Fracture Mechanics of Materials and Structural Integrity” organizers. 10.1016/j.prostr.2019.07.026