| abstract |
An improved brazing process increases the strength and longevity of joints between stainless steel tubes and aluminum fins. The process is especially useful in joining tubes and fins of HVAC secondary heat exchangers and high chrome steels and aluminum. The process is comprised of first plating stainless steel tubes with nickel before applying a brazing flux containing potassium fluoroaluminate complexes such as a NOCOLOK® flux. Subsequently, aluminum fins are pressed to the tubes and flux. The entirety is then brazed in a controlled atmosphere brazing oven. The aluminum becomes metallurgically bonded to the flux, nickel coating, and other constituents of the tubes. |