Abstract
Braze Pressure Welding (BPW) had been invented as the new joining method for the ordinary steel piping. BPW is the pressure welding with high frequency induction heating using the brazing filler as the interlayer metals. In the general idea of BPW, the liquid interlayer metals clear the joining surfaces, which are considered to be covered with the contamination layer of the oxide films and so on. The joining pressure discharges the liquid interlayer metals involving the oxide films from the joining interfaces. In addition, it forms the fillets around the joint. The base metals with cleared joining surfaces are pressure-welded by the relatively low joining pressure. Thus in BPW, the interlayer metals play an important role in welding the high performance joint. In this paper, the clearing property of the interlayer metals on the joining surfaces for clarifying the joining phenomenon was discussed. It was confirmed by the observation of the clearing effect, and the discharge of the inclusions produced by oxide films by the interlayer metals and the miniaturization of the inclusions by optical microscope and the EPMA analysis.
