| Abstract: |
Hardened hot work steels are subjected to high stresses in service as die cast molds. During brazing and, if necessary, quenching and tempering of these hot-work steels with Ni-based brazing alloys, brittle intermetallic phases can form in the brazed joint, which negatively affect the mechanical properties of the joint. In this study, the influence of current assisted brazing (ECAB) with the simultaneous use of a Ti inoculated Ni 620 brazing foil is investigated. The influence of the applied current and Ti inoculation on the microstructural evolution between the Ni base brazing alloy and the hot work steel is analyzed and evaluated by SEM/EDS. Also, the properties of the brazed joints are spatially analyzed using nanoindentaion, characterization and correlated with the SEM/EDS measurements. The ECAB shows a strong effect on the composition and phase fractions in the filler metal. Also influenced is the extent of the diffusion zone. Through the additional Ti inoculation, the formation of remaining brittle phases in the microstructure and also the extent of the diffusion zone can be specifically manipulated. Up until now, ECAB compounds have been less researched. For the first time, the presented study additionally combines and investigates ECAB with Ti inoculation. This has the potential to make future brazing processes faster, more energy efficient and overall more economical.
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