Abstract

The paper considers questions about the features of strip electrode overlay welding of the sealing surfaces of industrial pipeline fittings for nuclear power plants (NPPs). The analysis of literature data, scientific publications and research results on problems associated with automatic overlay welding with strip electrodes are performed, and the most perspective type of a surfacing strip for overlay welding of the sealing surfaces of pipeline fittings is selected. The main component of any type of fittings is the sealing surface which can be obtained by electric arc overlay welding. Sealing overlay welding is used when the fitting material prevents obtaining a satisfactory quality of the sealing seat surface. The surfaces considered are subject to wear as a result of mutual friction, dynamic and chemical impact of the medium. Operational reliability and durability of pipeline fittings for NPPs depend on the valve gate tightness determined not only by the properties of the alloy but also by the quality of the sealing surface. Overlay welding can be one of the main causes of defects; therefore, a qualitative and rational approach to the technological process of overlay welding, the availability of surfacing materials, and the technical condition of equipment and accessories are needed.

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