Flash butt welding corrosion of mooring chains

Abstract

Flash butt welding is a resistance welding process that offers great advantages due to its high thermal efficiency, simplicity and high speed, makes it ideal for welding mooring chains. Despite its advantages, numerous corrosion problems are still being found in practice, both in the heataffected zone and the weld line. Literature is scarce about it, limiting mostly to state the problem. The majority of the studies attribute this preferential corrosion to local changes in the microstructure that induce a galvanic coupling effect.Mooring chain R3 grade steel with preferential corrosion along the weld line has been studied from both metallographic examinations and electrochemical methods. Small differences were found in the microstructure of the heat-affected zone and base material (mainly composed of tempered martensite) but nevertheless, significant with respect to its corrosion behaviour. The corrosion mechanisms are discussed with particular attention to the electrochemical differences around the welding line.

Design of servo DC flash butt welder

“…This contact is repeated several times with electric and flying edge generation until a molten layer is formed over the entire joint surface, and then the welded joint is obtained by rapid advancement and pressure [1]. Flash butt welding technology with a high degree of automation has the advantages of excellent and stable welding quality, no need to use welding materials, field construction is not affected by climatic factors, short welding time, and high production efficiency [2][3][4].…”