Abstract: By means of orthogonal besign method, a new self-shielded flux-cored wire with CaF₂-TiO₂-MgO slag system has been developed. The deposited metal of the wire is characterized by its high ductility and low-temperature toughness, refined microstructure and good technological properties in welding. It is a quality welding consumable matching the HSLA steel with 550 MPa strength level and suitable for welding important constructions.