[en] Nature of structures and properties of surfaced weld metal, modified with yttrium additions was studied. The metal, weld deposited on plates of the 20 steel by a standard E50A type electrode with 0.2; 0.3; 0.6; 1.0 and 3.0% yttrium additions in electrode coating, was investigated. 0.2-0.3 % yttrium modifying improves the structure of surfaced weld metal: grain is refined, grain boundaries are clarified, nonmetallic inclusion quantity is reduced which results in an increase (in 10 kgf/mm²) of yield strength and impact strength at plasticity preservation at a high enough level (psi and delta). During welding constructions operating at low temperatures it is most effective to use E50A electrodes with 0.3% yttrium addition