What Is The Difference Between Welding and Brazing – A Brief Guide

Welding is more than just fabricating or applying heat with electrodes and fusing metallic materials. While metal fabrication is a broad process, knowing the tools and techniques that are required for any metal-joining tasks is important. Sometimes, people use 'welding' and 'brazing' interchangeably without considering their differences. In this brief guide, we shall focus on their respective operations and differences.

What Is Welding?

It's a process of fabrication and fusion of two metals (or thermoplastic) with similar properties. This fabrication process requires high temperatures to apply some metal-joining techniques. Also, you can't weld dissimilar materials like copper and steel.

In welding, filler metals are added to welded joints (molten material), and they get stronger when cool. You'll need a source of energy to weld. Some common sources include oxy-fuel, ultrasound, and electric arc (electrical).

Other sources are friction, laser, and electron beams. While melting the two metals, welders need to protect the filler metal from contamination or oxidization. Also, applying too much heat weakens the weld and alters the metal’s properties.

What Is Brazing?

Brazing is a method of joining two or more metals like copper, silver, and aluminum. Also, the technique is different from welding. Usually, brazing techniques work by applying heat to melt the filler metal (alloy). This molten alloy forms a bond between the metal pieces.

When the filler metal is hot, it flows (wetting) into space through capillary actions. There's a chemical reaction between the metals and their braze alloy. However, if there's an interfering layer between these workpieces, you'll have a weak braze.

Brazed metals are susceptible to oxidation effects (corrosion). With a flux like borax, welders can prevent oxides formations on metal during brazing. The flux is a special fluid that enhances wetting and allows the filler to flow freely. With its viscosity, the flux helps to clean metallic surfaces and ensures a firm bond. Also, you can apply flux is in welding, soldering, and brazing. Learn more here: https://science.howstuffworks.com/brazing.htm

Differentiating Brazing and Welding Processes

The uninformed might refer to both brazing and welding as soldering processes. While this information is wrong, soldering involves the application of flux. However, soldering can't be used interchangeably with either brazing or welding techniques. Here are some differences between brazing or welding techniques.

• Material Type: Welding involves melting of two metals, and fusing them with an electrode. While the metals in welding have similar properties, brazing works for dissimilar materials. Also, brazing techniques are ideal for joining multiple materials.

• Contaminants: During welding, the heat often burns out contaminants. However, it's important to clean metal surfaces before welding. When these contaminants are not combustible, the heat mixes them molten metal.

It's a different application from brazing techniques because this process uses less heat. So, we shouldn't expect the contaminants to burn out. During the process of brazing, the low heat converts contaminants into solid layers. The failure to clean metal surfaces before brazing causes these tough layers to prevent bonding.

Joint design: Normally, the process of welding two metal pieces applies molten beads on their edges. In brazing, it's the whole areas of the metals' surface that are joined. However, you might find little fillets on the edges of the metal. These side fillets help to improve the joint strength by at least 50%.

Process: The process of applying molten beads during brazing is through capillary actions. However, welding techniques depend on fusion. 

Temperature: Temperature is an important factor in fabrication. During the process of brazing, the wire (filler) must have a lower melting point than it's adjoining metal. This process is different from welding because the filler metal's melting point is higher than its adjoining metals. When we consider melting points, welding and soldering have similar processes.

What Is Tungsten Inert Gas (TIG) Welding?

The Tungsten Inert Gas (or gas tungsten arc) technique is an arc welding process. This process uses gas and non-consumable electrode to form and protect joints. TIG welding technique may come from the use of tungsten electrodes. Usually, the heat application on base metals and tungsten electrodes come from an electric arc. Learn about the electrode holder in this article. 

One of the advantages of using the TIG welding technique is the high melting point of tungsten electrodes. Normally, TIG welding machines are used by highly-trained welders. While it's tough to maintain the arc, TIG welding doesn't produce spatter or loss of filler metals.

What Is MIG Welding?

The metal inter gas arc welding (MIG) is also called gas metal arc welding (GMAW). When a MIG welding torch is triggered, the wire comes out of its guide and gas nozzle. During this process, the MIG Welder feeds a wire (filler metal) into the weld continuously. Without these fillers (wires), it's impossible to weld the two metal materials. Sometimes, people refer to this process of welding as 'wire welding' because the wires act consumable electrode.

Final Note

According to welding experts, applying brazing and welding techniques require concentration. Regardless of their benefits, metal fabricators need efficient machines. It's important to know the differences between them and choose wisely. With this article, buyers can get durable and well-designed products easily.