Microstructure and Mechanical Properties of 16MND5/309L/308L/Z2CND18-12N Dissimilar Metal Weld

The chemical compositions, microstructure and mechanical properties of 16MND5/309L/308L/Z2CND18-12N dissimilar metal weld(DMW) which was manufactured with French nuclear power technologies were analyzed. The results indicate that the chemical compositions of main parts of the DMW met the requirements of relevant standards and there was a significant change across 16MND5/309L interface. The microstructures of 16MND5 and Z2CND18-12N steel were upper-bainite and equiaxed austenite respectively. The microstructures of 309L and 308L weld were dendritic austenite with a little δ-ferrite. The 16MND5/309L interface had a thin layer of martensite. The hardness distribution across the DMW was not homogenious and the 16MND5/309L interface exhibited the highest hardness. Carbon migration and other properties of the DMW were also discussed.