Using the PuroBrite™ System to Braze Stainless Steel: The Importance of the Furnace

Providers of brazing services have a process for ensuring that stainless steel assemblies emerge from the furnace with strong joints and a bright surface. However, not all stainless steel brazing processes are created equal. Some brazing processes result in a higher first pass yield rate than others, and the reason why often has to do with the furnace a company uses for brazing. The performance of the furnace has a direct impact on a company’s first pass yield rate, which in turn impacts how quickly work orders are completed and delivered.

Furnace Variables in Brazing

The brazing process has several furnace related variables that determine the quality of finished assemblies. One of the most important variables is the atmospheric control of a furnace. Although all atmosphere-controlled and vacuum furnaces produce a “pure” atmosphere that lacks oxygen, the purity of the atmosphere can vary from furnace to furnace. Creating a good brazing process is dependant on using equipment that creates a truly pure, oxygen-free atmosphere. Otherwise, assemblies will experience some degree of oxidation.

Another important variable is the duration of the heat treatment process. It is well known that the longer stainless steel is treated at high temperatures the more likely it is to oxidize. Just as some furnaces are inefficient at creating an oxygen-free atmosphere, some furnaces heat inefficiently. Inefficient heating could have several causes, from the breakdown of insulation in the furnace to broken heating elements. Regardless of the cause, the result is always the same: assemblies must stay in the furnace longer in order for the filler metal to distribute the work pieces.

A third important variable deals with the type of furnace that is used. Assemblies that require the highest joint strength (e.g. assemblies for aeronautical equipment that will experience high g-force) are typically treated in a vacuum furnace that removes all gases from the heating chamber, thus preventing even the slightest degree of oxidation between the base metal and filler metal. When these types of assemblies are created using other furnaces, there is a greater chance they will fail dimensional stability tests; or, worse yet, prematurely fail during service.

How Franklin Brazing can Help

If you need strong, bright stainless steel assemblies, Franklin Brazing have the equipment and expertise to do the job right. Using our PuroBrite™ system to braze stainless steel, we achieve a first pass yield rate of over 99 percent. Unlike using some brazing systems, using our PuroBrite™ system to braze creates assemblies that consistently demonstrate excellent dimensional stability and appearance. For more information about using the PuroBrite™ system to braze stainless steel, call us today at (800) 450-7822, or click here to use our contact form.