Vacuum Brazed Weldments
Brazing done in a vacuum furnace is normally associated with smaller components and assemblies. 聽91传媒 has developed fixturing techniques and processes that enable the joining of larger components.
One such project was successfully accomplished for an OEM for thin film applications. 聽A regular customer for stress relieving stainless steel weldments recently utilized Solar鈥檚 vacuum brazing capabilities where welding was not possible.
91传媒 vacuum braze process was used because welding tubing to a plate would have resulted in a severely warped assembly. Additionally, vacuum brazing prevents oxidation and results in consistent tensile strength throughout the assembly.
Stainless steel tubing was vacuum brazed to stainless steel plates to form seven assemblies. 聽Cal Amenheuser, Vice President of Brazing, was very pleased with the result stating, 鈥渢he finished result looked like a single piece of stainless steel.鈥� 聽Two circular assemblies were about 20 inches in diameter. 聽The other five were rectangular, about 40 inches long by 12 inches wide.
The Vacuum Braze Process
– Hand wiped every assembly to make sure that all the dirt and oils were removed prior to alloying.
– Placed an eighty thousands (.0080″) bead of nickel braze alloy along both sides of tubing on the plate. A full fillet was formed on both sides of the tube forming a complete bond to the plate.
– Stop-off paste was placed on the plate directly behind the nickel braze alloy to assure the nickel braze alloy would stay in the joint area and not spread or flash across the surface of the plate.
– The assemblies were fixtured on half inch graphite boards sitting on moly grids to assure plate flatness during the braze run.
– The assemblies were loaded into a vacuum furnace, brazed at 1930 degrees F. in a vacuum level below 1×10-4 torr.
– Post braze, the stop-off paste was removed from each assembly.