Peculiarities of process of gas-shielded arc welding using flux-cored wire are considered. Given are the data on metallurgical characteristics and classification of the gas-shielded flux-cored wires with different core types as well as examples of their successful application in industry. 6 Ref., 1 Long-term application of solid flux-cored wires in mechanized and automatic gas-shielded welding was mainly caused by their availability and small price. Eventually, understanding of technological and economic advantages of application of the flux-cored wires was verified by the results of analysis of expenses for welding performance and quality of welded joints. This allows the flux-cored wire taking the leading position in performance of welding operations in different branches of industry and building in countries with high level of economic development [1]. Gas-arc welding using the flux-cored wire allows responsing the demands of manufacturers of welding structures, since it differs by versatile, good operation characteristics and high efficiency, that provides for significant reduction of economic expenses.Today a variety of types of the flux-cored wires are classified on international standards ISO in accordance with class of steel, for which they are designed. Standard ISO 17632 [2] is used for the most widespread classes of normal strength structural steels, and ISO 18276 [3] is applied for high strength ones. Shielding gases for performance of gas-arc welding are classified on standard ISO 14175 [4]. The classification in accordance with indicated standards is further used.The specialists in area of fusion arc welding know well that change of solid wire to flux-cored one does not require variation of basic technology or application of another equipment. Current welding equipment provide for a wide range of regulation of statistical and dynamic characteristics of power sources with the help of microprocessor technology, that allows setting of the optimum welding parameters for each wire type. Feed mechanisms of the semi-automatic machines are as a rule equipped with two pairs of rolls for reduction of wire pressure, prevention of its deformation or break of geometry, that deteriorate wire feeding through the hoses.Metallurgical characteristics of gas-shielded flux-cored wires. Established classification of the flux-cored wires on type of flux core, which is included into international standards, divide them on three main types, namely rutile, basic and metallic.Rutile type (on title of mineral -rutile) includes the wires with basis of a slag system composed of titanium oxides in combination with other oxides (for example, silicates and alumosilicates), formed in melting of low-basicity slags. Change of composition and application of fluxing agents reveal wide capabilities for regulation of technological properties of these wires. They are divided on rutile ones with slowly setting and rapidly setting slag according to the welding technological properties, that determines a possibility of their application for...