Brazing Term Paper

Brazing Term Paper

In the HVAC/R industry, technicians will use copper tubing everyday to connect heating and cooling systems and fix appliances.   In this event, technicians need a system to make the connections and repairs to the copper tubing.   In HVAC/R, the best system to use to connect fittings and equipment is brazing, also called silver brazing or hard soldering.   This is the best for the industry, because of its great tensile strength.   The brazed joint or fittings are often stronger than the two metals being bonded together.   These joints repel gas, liquids, vibrations, and shock and are unaffected by normal changes in temperature.   Brazed joints also can withstand much higher pressure and temperatures than regular soldering.   This is a small sample of why the HVAC/R industry uses brazing for almost all of their connections.   In the following paragraphs, you will understand the use and different techniques used in brazing. (www.inductionatmosheres.com)

Brazing is a method of joining two pieces of metal together with a molten filler metal.   The joint or socket is heated above the melting point of the filler metal, but below the melting point of the metals being joined.   When filler metal is molten, it flows into the gaps of the socket by capillary action and makes a strong metallurgical bond as it cools.
Brazing filler metals, suitable for joining copper tubing, are alloys containing 15% to 60% silver or copper alloys containing phosphorus.   There are many alloys out there to choose from.   The type of joint dictates the brazing material used.   All connections are not copper to copper.   Some may be copper to steel, copper to brass, or brass to steel.   These different connections require different silver content brazes.  
For this paper, we are going to stay with copper to copper tubing, which in the industry is common to use 15% silver content brazing stick. (Whitman, Johnson, Tomczyk, and Silberstein)

To combine copper tubing together, this can be done a few...