WELDED SEAM METAL FOR JOINING HIGH-STRENGTH LOW-ALLOY STEELS Russian patent published in 2006 - IPC B23K9/173 B23K35/22 

FIELD: metallurgy, namely welded seam metals for joining high - strength low - alloy steels, welding consumable wire.

SUBSTANCE: metals of welded seams have microstructure having 5 - 45 vol % of acicular ferrite and at least about 50 vol % of drag martensite, upper bainite, lower bainite, granular bainite or their mixture. Yield limit of welded seam metal is at least about 690 MPa; temperature of its transition from plastic state to fragile one is less than -50°C and it is determined according to curve of relationship of rupture energy of Charpy sample with V-shaped notch from temperature. Welded seam metal may contain, mass %: carbon, about 0.04 - about 0.08; manganese, about 1.0 - about 2.0; silicon, about 0.2 - 0.7; molybdenum, about 0.3 - about 0.8; nickel, about 2.3 - about 3.5; oxygen, about 0.0175 - about 0.0400 and at least one additive selected from group including zirconium, about 0.04 but no more and titanium, about 0.02 but no more. Seam is formed by electric arc gas-shield welding by means of metallic electrode with use of welding consumable wire. Metals of welded seam according to invention may be used for electric arc gas-shield welding of main pipeline erections.

EFFECT: high strength, improved impact viscosity and resistance against hydrogen cracking of metals.

42 cl, 16 dwg, 2 tbl