Shielding gas brazing of martensitic stainless steel with copper free silver based filler metals

In the present work, the applicability of the copper free silver based alloys Ag-15Mn and Ag-5Pd as filler metals for shielding gas brazing of the martensitic stainless steel X3CrNiMo13-4 was investigated. The joints were examined with respect to their microstructure, their corrosion behaviour in aequous NaCl solution as well as-in the case of the specimens brazed with AgPd5-their mechanical performance under tensile and torsion loading. Specimens brazed with Ag-15Mn showed pronounced oxidation in the Ar/H-2 shielding gas atmosphere as well as a low corrosion resistance in 0.5M NaCl solution. The filler metal Ag-5Pd showed very good brazing results. With this filler metal, defect free and corrosion resistant joints with an ultimate tensile strength of 800 MPa and a low cycle fatigue strength of 490 MPa could be produced.