Differences between Welding, Brazing, and Soldering

Welding, brazing, and soldering are all methods of joining two pieces of metal together. These terms are often used synonymously by laymen. However, technically there are differences between them.

Read on to learn the differences between these three processes and when manufacturers use each process. However, before that, we believe it’s necessary to give you a brief overview of each process.

What is Welding?

Welding is a process of connecting two materials by melting and forming a strong bond. The base metals are heated at very high temperatures (going beyond 6,000) using a flame torch or arc and then fused.

Welding commonly suits joining two similar metals, and joint strength is comparable to the original base metal.

Types:

Welding is a common term used to describe a wide range of welding techniques. The commonly used welding types are Tungenston Arc Welding (TIG), Shielded Metal Arc Welding (Stick welding), flux core welding, etc. These welding techniques have slight differences, which are discussed in other articles.

Pros:

• Produces high-strength, low-cost joints.
• Doesn’t necessarily require a filler.
• Equipment is portable and can be carried anywhere for indoor projects.
• Its use case is quite huge and can be used in various projects (ranging from automotive to underwater applications).

Cons:

• Requires specialized equipment and expertise, making it unsuitable for the layperson without these resources.
• Low productivity cycle since welding only takes place for just 60% of the total production time.
• Potential dangers are involved when working with high temperatures and sparks; proper protective gear must always be worn while welding.

Ultimately though, the upsides of welding far outweigh the downsides – it produces reliable and stable connections that will last for a long time.

What is Brazing?

Brazing is a process of joining two metals or other materials using a filler metal that has a lower melting point than the original base material. The process is similar to welding but takes at a relatively low temperature (below 750 ℃).

You might hear brazing being referred to as “hard soldering” because it is similar in nature and purpose, but it allows for thicker metals to be joined.

Types of Brazing

Based on the heating sources, brazing has four types; torch/manual brazing, induction brazing, resistance brazing, and vacuum brazing.

Pros:

• Unlike welding, two dissimilar metals can be joined.
• Temporary joints; can be removed in the future.
• The joining is achieved at a lower temperature.
• Parts of varying thicknesses can be joined.
• No post-heat treatment is required.

Cons:

• Joint strength is not strong as welding.
• Not suitable for permanent joints and high-heating applications

What is Soldering?

Soldering is a process of joining two pieces together with an alloy called solder and a heat source, such as a soldering iron or torch. This popular technique has been around for thousands of years and is used for combing metal surfaces in jewelry and designing circuits for the electronic industry.

Types of Soldering:

Unlike welding, soldering doesn’t have many types. It is classified as hard or soft soldering based on the working temperature. The one which takes place at a lower temperature than 450 ℃ is soft soldering. While the process which takes place at a slightly higher temperature is hard soldering, often called brazing.

Although soldering is a time-honored way of fabricating metals, there are both advantages and disadvantages to using this method.

Pros:

• Used for small-scale applications like joined wired connections.
• Removable joint.
• Easy method; a layman can perform it after a few tries.

Cons:

• Not suited for large-scale applications.
• Produces weakest joints.

Differences between Welding, Brazing, and Soldering

Welding, brazing, and soldering are three important fabrication processes for joining metals and alloys. While these processes may appear similar to the untrained eye, there are considerable differences between them.

Let’s take a closer look at how these three techniques differ in terms of temperature difference, joint strength, filler metal, and applications.

Temperature:

One of the main differences between these three joining processes is temperature. The temperature can go much higher in welding than in brazing and soldering. For instance, in arc welding, the temperature goes beyond 5,000 ℃. Whereas brazing takes place in intermediate temperatures, i.e., 450 to 750 ℃. The soldering occurs even at a much lower temperature (below 450 ℃).

Strength of Joint:

Welded joints are much stronger than brazed and soldered joints. Though the joints created through brazing may not be stronger than welded ones, they significantly have more strength than soldered joints.

The strength of these processes in the following order:

Welding >> Brazing >> Soldering

Filler Materials:

Depending upon the application, the welding operation can be completed with or without using any filler material. However, a filler material is required for brazing and soldering.

Application:

Though each of these processes technically does the same job, they differ in their applications. For instance, the soldering process is widely used in the electronics industry; for soldering wires on circuit boards.

The welding process has a wide range of applications in every industry; it is used to create permanent joints from the aerospace industry to the automotive industry.

Brazing often finds applications in the pipe and pressure vessel industry. It is used in leak-proofing metallic pipes, valves, connectors, etc.

Since we have covered in detail the differences, let’s see a summarized view of the differences between these three metal joining processes:

Conclusion

The three typical fabrication processes, welding, brazing, and soldering, may seem similar to a newcomer. However, there are a few differences. The major one is their operational temperature; welding occurs at a very high temperature (beyond 6,000 ℃), while soldering often takes place at temperatures below 450 ℃. The strength of joints also varies; welding produces the strongest while soldered ones are the weakest. Additionally, welding may not join two different metals, while you can solder or braze them.

Despite these differences, each of the processes is designed for some specific use cases. For instance, welding is used in automotive industries for high-end permanent joints. Whereas in some moderate applications, like leak proofing pressure vessels or pipes, brazing is used. Finally, soldering is used in very small-scale applications, for instance, designing electronic circuit boards.