Steels with Yield Strength Higher than 700 MPa for Metallic Structures and the Strength of Their Welded Joints

—Thick rolled products (plates) made of high-strength S690 steels (σ y ≥ 690 MPa), which have not been used in the Russian building industry to date, are shown to be used in bearing welded metallic structures. Technological approaches, which can impart the high service properties that meet the requirements of norms and records to thick-sheet steels (50 mm thick or larger), are described. The advantages of hardening of rolled products up to 50 mm thick by thermomechanical rolling followed by rapid cooling and by thermal toughening of rolled products more than 50 mm thick are revealed. Criteria are proposed to determine the properties of the welded joints of S690 plate steels and to ensure service ability of these joints. The results of testing real welded joints of rolled products made of the S690 steels fabricated according to the proposed technologies are presented.