Development of economically alloyed structural steel of strength classes 345 and 390

Structural steels used in the production of welded metal structures in contemporary domestic and overseas practice are analyzed. Common tendencies and differences from strength classes used most frequently are revealed in steel alloy systems used in the production of thick rolled sheet. Simulation of normalizing and thermomechanical rolling, and also normalizing for steel of the alloy system C‐Mn‐Si‐Nb, is performed under laboratory conditions. The possibility is demonstrated of preparing rolled product of strength class 390 with an increased level of brittle failure resistance from economically alloyed steel using thermomechanical (normalizing) rolling technology.