Brazing is considered one of the most effective and efficient ways to create solid, durable, strong and leak-proof joints. Unlike welding that required the welder to heat the base metals to create a fusion of the two, brazing allows a third metal, an alloy, to liquefy and move between the two base metals, forming a joint that is stronger than any of the metals on their own. Choosing the right braze material is therefore essential to create just the joint that you need.
Choosing the Metal or Metals
You can choose a variety of braze material metals that are very different from each other. Unlike welding you don’t want either metal to actually reach the point of melting, so temperature issues are much less problematic. However, you do need to be cautious of possible reactions and expansion issues as you will heat the filler metal.
It is important to keep in mind that the metal braze material options that you choose have a higher melting point or heating point until expansion occurs than the filler metal that you choose.
Filler Metals
When it comes to choosing hi-temp braze alloy material with regards to the filler you have several different options. The most common alloys used in filler material include base metals with combinations of nickel, cobalt, manganese, boron, silicon, iron, chromium, tungsten and a host of others including some of the rare earths.
The base metals used in braze material fillers include nickel, cobalt, silver, gold, aluminum and copper. Adding the additional alloys creates different attributes of the filler metal including high temperature durability, increased joint strength, reduced or increased melting temperature or actually creates a more durable joint under specific usage requirements.
Type of Brazing Method
The type of brazing method will also be an important consideration when you are selecting a braze material, particularly a base metal and alloy combination. Some base metals are not appropriate for different brazing processes. For example, nickel, cobalt and gold are not recommended as base filler metal bases if you want to use a dip brazing method while silver, aluminum and copper will work well using this method.
Working with a company that specializes in brazing is the best way to ensure that you are using the correct types of braze material for each component of your project.
