Arc-brazing of high strength stainless steel for transport applications

This paper describes a feasibility study aiming at defining the potential and benefits of arc-brazing of high strength stainless steel over conventional arc welding. Arc-brazing experiments of high strength austenitic stainless steel were carried out in both sheet butt joint and RHS tube cruciform (fillet) joint configurations using commercial filler metal. Subsequently, the resulting joints were examined and judged by optical macrographs of joint cross sections, hardness measurements and tensile testing. The experimental results show that the static mechanical properties of the best arc brazing variants were fully comparable with those of the welded references. Brazed with synergetic pulsing, the nominal tensile strength is at the same or higher level with welded reference. Without pulsing, the best brazed specimens show strength values of 75 to 90% of that of the welded reference. The goal of reducing the heat input and thus affecting the base material softening was not reached in this limited series of experiments. However, the hardness profile across the joint and the consequent mechanical properties could be modified with brazing procedure, although the welded reference sample shows less softening than any of the brazed variants. From economical point of view, the higher cost of a copper based filler metal should be compensated by benefits such as, e.g. improved joint properties, increased productivity or decreased number of preceding and/or subsequent working phases. In this relatively limited screening study such benefits could not be demonstrated