EXPERIMENTAL RESEARCH OF THE DUPLEX STAINLESS STEEL WELDS IN SHIPBUILDING

Duplex stainless steel is used in shipbuilding increasingly because of its good mechanical properties and marked corrosion resistance. This steel has a two phase structure (austenite-ferrite) which is sensitive on heat input during welding because of the possible ferritisation appearance, that is, increase in ferrite content in the area of heat effected zone (HAZ) which can lead to loss of mechanical and corrosion properties. Work with duplex stainless steel requires special attention in every phase of production process, from storage, material handling, up to welding and welded joint surface treatment, in order to achieve a high quality welded joint and assure long-lasting corrosion resistance of the structure. In the beginning, this paper explains basic characteristics of the duplex stainless steel. In the experimental part, macrostructure, microstructure and corrosion resistance testing of butt welds, fillet welds and welded studs were performed. Results of the research are a basis for conclusions and suggestions for successful applications of duplex stainless steel in shipbuilding.