One of the most famous charts ever used in brazing is the famous (infamous?) strength vs. clearance chart created from work done in the Handy & Harman laboratories in Fairfield, Conn., back in the 1930s.
The first, and obvious, point to make about dimensioning braze fillets on drawings is that once a braze-fillet size is specified on a drawing, it must be inspected and measured to verify compliance.
It is NOT recommended that either dye-penetrant inspection (DPI) or fluorescent-penetrant inspection (FPI) be used for inspecting brazed joints, particularly on any parts for which subsequent braze repair may be required!
A number of corporations use radiography as an important part of their accept/reject criteria for in-house brazing operations, believing that X-ray films can always show any imperfections, voids, etc. in any of the components they braze.
Extensive testing over the years in many places has shown that the best surface (generally speaking) for brazing is the "as-received" surface roughness of the material coming into the shop.
The VTS provides a unique way to determine exactly what kind of braze clearances can be tolerated in your particular furnace with your particular base metals and BFMs.
Furnace brazing is a common brazing process around the world, and I have witnessed many brazing furnaces in action in many countries – from here to mainland China.
Brazing is a versatile process used in many industries around the world to permanently join materials together at elevated temperatures (usually between 1100˚F and 2300˚F) using a brazing filler metal (BFM) with a melting point that is above 840˚F (450˚C) but always below the melting point of the materials being joined.
This question is not an uncommon one. Although I have never personally seen any kind of chart give me an "expected life" for fixture materials, it is important that people understand that there are a number of factors that will control the "life expectancy" of fixturing materials used in brazing, and all of them relate to the service conditions that the fixtures will encounter during the brazing process.
As mentioned in the previous blog entries, brazers commonly encounter voids in brazed joints and often wonder where they come from and how to avoid them in future brazements.
As mentioned in the previous blog entry, brazers commonly encounter voids in brazed joints and often wonder where they come from and how to avoid them in future brazements.
As mentioned in the previous blog entry, brazers commonly encounter voids in brazed joints and often wonder where they come from and how to avoid them in future brazements.
A common occurrence (unfortunately) in the brazing world is the need to join two parts together by brazing in which the brazing gap is too large – i.e., in the range of 0.010 inches (0.25 mm) or larger. Ideal brazing clearances should be a maximum of 0.000-0.005 inches (0.00-0.125mm) for most brazing filler metals (BFMs).
Many people use silver-based brazing filler metal (BFM) when torch-brazing (i.e., flame-brazing) a variety of base metals such as copper, copper alloys and many types of steel (including stainless steels).
Over the years I’ve helped many brazing shops resolve common brazing problems (such as leakers, non-wetting surfaces, etc.). In evaluating these situations, it is not uncommon to discover that sub-components (such as brackets or fittings, etc.) from outside suppliers can actually be the troublemakers!
Brazing, when performed correctly, is a joining process that produces a permanent bond between two or more materials by heating them to a temperature above 450°C (840°F), but lower than the melting-temperature of any of the materials being joined.
