Brazing vs other Metal Joining

When we talk about the metal bonding processes, we come through a lot of options. They are:

Each of these metal joining processes have their own benefits and drawbacks. Some processes are more suited to a particular applications and some to others. When strong and permanent metal joins are required, then the choice usually shortens to two processes, welding and brazing.

Comparison Chart of Different Bonding Processes
While comparing different bonding processes, we have to consider several factors, such as strength, flexibility, economy, energy used, control and many others. These factors play determining roles in the performance of bonds.

 

	Adhesive Bonding	Mechanical Bonding	Soldering	Welding	Brazing
Strength	GOOD	GOOD	BETTER	BEST	BEST
Flexibility	GOOD	GOOD	BETTER	BETTER	BEST
Economy	BETTER	BEST	BETTER	GOOD	BETTER
Energy Used	BETTER	BEST	BETTER	GOOD	BETTER
Control	GOOD	GOOD	BETTER	BEST	BEST

 

Some Common Differences

• Brazing or welding are given preferences when strength and permanence are main considerations. Brazing is considered a more robust process, a filler metal is always used and usually the whole joint area is heated at the same time. It provides absolvitory joint clearances, fixturing than welding.
• However if strength is not a vital factor in the bonding or if the joint can be disassembled in the future then in that case adhesive bonding, soldering or a simple mechanical fastening method are probably better options
• Brazing, welding, and soldering are similar in various respects, but there are important differences between them that set them apart from each other. Soldering is a low temperature process and is performed below 450°C but can't produce strong joints. On the other hand, welding requires most heat energy as it melt the base metals and fuse them together to form joints. The welded and brazed joints are as strong as the metals being joined and even stronger. It is ideal for the processes, which benefit from localized and pinpoint heating. Welding isn't considered proper for two different metals having different melting points. Also it is difficult to apply to linear joining.
• The physical characteristics of the parts and joint area is also important to consider before brazing. If the parts to be joined are thick and can withstand higher temperatures then welding can be suitable. As brazing works at lower temperature it is suited to thinner parts. It can minimize metal warping and distortion. Spot joints are easily welded or brazed, but linear joints are easier to braze.

Soldering
It is a metal joining process in which two or more metal items are bonded together by melting and flowing a filler metal into the joint. The soldering filler metals have a relatively low melting point.

Adhesive Bonding
It is a bonding process for joining parts, such as polymers to metals, metals to metals, ceramics to metals, etc using bonding chemicals or materials known as adhesives. The adhesive-bonded joints can withstand shear, tensile, and compressive stresses, but they do not exhibit good resistance against peeling.

Mechanical Bonding
It is a conventional bonding process used to quickly bond together two or more layers of material. Ultrasonic bonding is one example of a mechanical bonding technique.