Brazing is a process of joining two metals with a filler metal called a brazing alloy. The filler metal is melted at temperatures which are typically between 840 and 1040 degrees Celsius and is distributed between the closely fitted parts by capillary action. Brazing is commonly used to join dissimilar metals, create joints between metal components, and repair heat-affected zones. Precious metals such as gold, silver and palladium are also applied to components in the form of a brazing alloy when the need arises.
The principal components of a brazing filler alloy are a base metal and the brazing alloy. The base metal is typically either copper, silver or nickel and it provides the strength and durability for the joint whereas the brazing alloy is the combination of metals that form the active filler material. This filler material provides the desired composition, melting point and ability to aid in the flow of the alloy into the joint. The brazing alloy must closely match the coefficient of thermal expansion of the base metal in order for it to flow neatly and completely throughout the joint.
Brazing is a popular process for joining two metals because it is a less expensive and less demanding process than welding. Less energy is required as well since brazing only heats the area around the joint while welding heats the entire component. Brazing also produces less distortion of the joint area since it works at lower temperatures than welding.
Brazing alloys are available in numerous combinations of the base metal and the alloy element. The most common types of base metals used include copper, brass, bronze and aluminum because of their excellent thermal conductivity capability. The filler alloy elements typically used include silver, gold, nickel, palladium, and phosphorus. The choice of alloy and the base metal used depends on the quality, price and durabilitiy of joint.
In order to ensure a good braze joint, proper surface preparation and cleanliness are two main requirements. The surfaces to be joined should be free of dirt, oil and other impurities. The surfaces should also be rough enough to create a strong mechanical bond between the two pieces. Care should also be taken to not overheat the joint or put too much pressure on the joint before the filler metal hardens.
Brazing can also be used to strengthen and repair components that have already been subjected to welding or heat treating. Brazing rods can be used to join cracks, strengthen fractures and restore eroded material. The joint can be easily welded, soldered and brazed in order to create the desired joint.
Overall, brazing is an excellent process for a variety of applications and industries. It is especially beneficial when joining two dissimilar materials and can also be used to repair heat-affected zones and welds. Brazing is simple to use, efficient and relatively inexpensive. With the right materials and preparation, it is also a quick and reliable method for joining and strengthening metals.
