Metallurgy of dissimilar laser beam welded lap joints of supra-ductile and ultra-high strength steels

Results of research on laser beam welding of a high manganese X30MnCrN16-14 (1.4678) to a press hardened X46Cr13 (1.4304), a dual phase steel (1.0944), and a press-hardened manganese boron steel (1.5528) in lap joint configuration will be reported. A pre-assessment of the local mechanical properties by micro hardness measurements revealed their uneven distribution over the weld zone. Based on metallographic inspection the underlying microstructures were revealed. By EDS analyses the local alloy constitutions were determined and assed by of COHMS diagrams. It was confirmed that in the combination with the high manganese steel the formation of ferritic phases, ferrite is largely suppressed to the favor of austenite and a' and e martensite. These findings were in part confirmed by nano indentation. The results allow an insight into the properties linked to melt transport but indicate some further research.