AeroMat Home      Exposition      To Register      ASM Homepage
Back to "Session 3: Welding of Stainless Steel and Steel" Search
  Back to "Welding and Joining Technologies" Search  Back to Main Search

Thursday, May 18, 2006 - 1:30 PM
WJT063.1

Chosen Aspects of 18-8 Stainless Steel Brazing by AgCu42Ni2 Filler Alloy

T. Babul, A. Nakonieczny, S. Kowalski, Institute of Precision Mechanics, Warsaw, Poland; J. Senkara, J. Jakubowski, Warsaw University of Technology, Warsaw, Poland; J. Kopec, WSK Rzeszów, Rzeszów, Poland

The paper deals with chosen issues related to application of AgCu42Ni2 alloy in brazing hydraulic, air- and fuel-operated pipes use in the aircraft engines. One of the alloy feature is a significant difference between solidus (771oC) and liquidus (893 oC) temperatures which is rather unusual for fillers. Hence, it has the tendency to split into two phases in the course of the joining process.

Brazing experiments were conducted in 10-6 Tr vacuum environment. Impact of different means of isotropic and anisotropic surface preparation (including sand blasting, polishing, wear cloth application, and nickel plating) on the filler spreading was tested. Surface area covered by the liquid alloy as a function of brazing temperature and time is also presented. Structures of obtained joints were investigated by optical microscopy, scanning electron microscopy, x-ray diffractometry, and micro-hardness measurements. A particular attention was attracted onto interfaces and diffusion layers. The paper presents also the analysis of phenomena that occur during the liquid front movement through the gap between two cylindrical surfaces.


Summary: The paper deals with chosen issues related to application of AgCu42Ni2 alloy in brazing hydraulic, air- and fuel-operated pipes use in the aircraft engines. One of the alloy feature is a significant difference between solidus (771oC) and liquidus (893oC) temperatures which is rather unusual for fillers. Hence, it has the tendency to split into two phases in the course of the joining process. Brazing experiments were conducted in 10-6 Tr vacuum environment. Impact of different means of isotropic and anisotropic surface preparation (including sand blasting, polishing, wear cloth application, and nickel plating) on the filler spreading was tested. Surface area covered by the liquid alloy as a function of brazing temperature and time is also presented. Structures of obtained joints were investigated by optical microscopy, scanning electron microscopy, x-ray diffractometry, and micro-hardness measurements. A particular attention was attracted onto interfaces and diffusion layers. The paper presents also the analysis of phenomena that occur during the liquid front movement through the gap between two cylindrical surfaces.