| abstract |
The welded structures are designed for construction and have a tensile strength of more than 900 MPa (130 ksi) and the weld metal has a rupture toughness that meets the cryogenic temperature requirements. The method of welding the parent metal comprises a welding step in which a welding process is used in a protective gas medium, argon-based protective gas and a melt welding wire, whereby a metal of the welding seam with a transition temperature of plasticity to brittleness is obtained - a temperature of -70 ° C (-1000 ° F), which metal has a fine-grained volume-centric cubic crystal structure comprising at least 50% self-return plate martensite and less than 250 per mm2 non-metallic inclusions with a diameter greater than 1000 nm defined on the surface of a welded metal weld plate. The metal of the weld seam contains iron and the following alloying elements in% by weight: carbon 0.06-0.10, manganese 1.60 to 2.05, silicon from 0.20 to about 0.32, nickel of 1.87 to 6.00, chromium of from 0.30 to about 0.87 of cobalt 0.40-0.56. The method also provides a welded structure with a tensile strength of greater than about 900 MPa (130 ksi). |