Electrometallurgy Today, 2021, №02



2021 №02 (06)

DOI of Article 10.37434/sem2021.02.07

2021 №02 (01)

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Electrometallurgy Today (Sovremennaya Elektrometallurgiya), 2021, #2, 47-53 pages

Structural criteria of strength and crack resistance of high-strength steels and their welded joints

O.M. Berdnikova

E.O. Paton Electric Welding Institute of the NAS of Ukraine. 11 Kazymyr Malevych Str., Kyiv, 03150, Ukraine. E-mail: office@paton.kiev.ua

Abstract
Regularities of formation of phase composition, grain, subgrain and dislocation structures at different technological parameters of welding, interrelation of the structure with a set of properties: strength, fracture toughness, level of localized strain and local internal stresses in the metal of high-strength steel welded joints were investigated. Welded joints of high-strength steels, differing by their strength and purpose, namely low-carbon ferritic-bainitic and bainiticmartensitic; high-carbon ferritic-pearlitic; and alloyed medium-carbon martensitic steels, were studied. Experimentalanalytical procedure for evaluation of a complex of physico-mechanical properties of all the structure elements by specific structural parameters was improved, and mathematical processing of the data was introduced. It allowed classifying the cracking conditions with respect to a set of structural components, taking into account the dislocation density and substructure features. Such an experimental-analytical approach to studying the regularities of metal structure impact on its strength, fracture toughness, local internal stresses and localized strain allows evaluation both of the local level of these values, depending on structural factors, and of the general tendency of the change in mechanical properties and crack resistance. Ref. 14, Tabl. 1, Fig. 5.
Keywords: high-strength steels; welded joints; phase composition; microstructure; dislocation density; fracture mode; mechanical properties; crack resistance

Received 08.04.2021

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