How welding, soldering, and brazing are applied

How welding, soldering, and brazing are applied

Introduction

There are many ways of joining or filling gaps in pieces of metals. Welding, soldering, and brazing are conventional techniques for doing this work. But, you need to have an understanding before applying any one of them. Don’t worry if you don’t know their distinctions, advantages, and applications. I am going to discuss in detail the three metal joining methods. I will deepen your knowledge therein by giving elaborate differences among these techniques. With an increased understanding, you will identify a suitable approach for your application. This write-up will guide you to make an informed decision.

What is the difference between welding, brazing, and soldering?

Welding involves joining similar metals by melting and fusing them using a filler material. By directing a concentrated heat on a joint, it softens the filler material and base-metals. This weld is more reliable than the base metals. The heating temperatures are above the melting points of the base metals and the filler.

In brazing, the heat melts the filler material, which joins the metals together by capillary action. The resultant joint is more reliable than the base metals. The brazing temperatures are lower; thus, they do not melt the base metals. These temperatures are also below the melting points of the base-metals. It can also join or fill dissimilar metals, unlike welding.

Soldering is a process of metal joining or filling that happens at lower temperatures. The molten filler uses capillary action to join base metals together. The joint formed is weaker than the base metals. It can join or fill metallic and non-metallic plates.

1. Welding

This process encompasses both the arc and gas welding. The arc-welding melting heat comes from the electric arcs. On the contrary, gas welding uses heat from the oxy-acetylene torch to melt metals. After joining the pieces together, the heated welding rod or filler material forms a weld. The welded joint is more reliable and permanent compared to the base metals. This method is more appropriate for joining a large assembly of metals. The following are the techniques used in arc welding.

Metal Inert gas welding (or MIG)

In this arc-welding process, a continuous heated solid wire moves into a weld pool. The welding gun pushes this wire and also feeds an inert gas into the pool. This wire completes the electrical circuit producing an arc on the workpiece. A shielding inert gas protects the weld pool from contamination. It w both thin and thick pieces of metal sheets. An arc makes the parent materials to melt and join them together. Compared to MMA, it’s flexible, suitable for mechanization, and has higher deposition rates. e

Tungsten Inert Gas welding (or TIG welding)

A pointed tungsten electrode produces a weld through arching. Mains power with a constant current provides an arc in an ionized inert-gas. The electrode wire and the welded joints don’t oxidize during this process. Shielding by the inert gas prevents contamination and oxidation. With autogenous welds, welding happens without filler metal. But, in most cases, a filler material is used to weld pieces together. This method is the best for welding non-ferrous metals and stainless steel. The weld produced is of the best quality and more potent than base-metals.

Shielded metal arc welding (SMAW)

It is a welding technique where a fluxed and consumable electrode produces a weld. An AC/DC operated welding machine produces an electrical arc that joins metal pieces. The electrical arc produces high-temperature plasma, which melts the electrode and the workpiece. A joint forms when a pool of molten metal cools. The fluxed electrode rod leaves a coat on the weld, which prevents it from contamination. Gases produced acts like an oxidation shield. Shielded arc welding is simple to learn and performs large scale chassis fabrication in industries.

2. Brazing

With brazing, you will make stiff metallurgical and permanent metal joints. This type of welding requires lower temperatures to melt metals compared to welding. These lower temperatures don’t melt parent metals, but its heat melts the filler-metal.

By capillary action, the molten filler joins the metal pieces together into a joint. The metallurgical bond strength produced is more durable than the base metal. Unlike shielded metal arc welding, brazing joins or fills dissimilar metals. The following are common types of brazing techniques.

Torch brazing

Torch brazing process is done manually or automated. Brazing of similar and dissimilar metals happens on a small scale or large scale. Here, a torch melts the filler material, which in its molten makes a joint. The principle of capillary action brings the metal pieces together. A stronger bond that exceeds the parent metals forms the joint. The temperatures of the torch flame are lower such that they cannot melt the metal workpiece. For a perfect joint, the workpiece needs to clean and free from contaminants. It is the commonly used brazing method.

Furnace Brazing

Being a semi-automated process, it joins the workpiece together using dissimilar lower filler metal. With this brazing procedure, it is possible to join simple and complicated multi-joints. Producing many brazed parts is done in a furnace; thus, most brazing industries embrace it. The computer does heat cycling; achieving uniform brazing is easy. With heat localization, you can make precise joints compared to manual brazing. Since furnace brazing occurs in a vacuum, oxidation and contamination don’t affect the workpiece.

Braze welding

This type of brazing uses fluxed bronze or brass fillers to join the metals. The perfect way to join galvanized metals is by using Braze welding. The melting point of the filling material is lower than that of the base metal. Here, a stable joint is formed by capillary action when the molten filler cools. The joint formed is more robust and withstands more loads than the parent materials. This process can join thinner metal sheets of up to 0.2 mm. The limitation for thicker metals is up to 3 mm.

3. Soldering

Soldering is a metal joining process where the filler material melts at lower temperatures. Most soldering temperatures are below 450 degrees Celsius. The molten filler material makes the base metals to unite by capillary action. The soldering heat is below the melting points of the metal workpiece. For the best joint formations, the base metals should be clean and free from lubricants. Compared to welding and brazing, a soldered joint is weaker than the parent metals. The following soldering techniques are popular in making metallurgical bonds in industries and DIY experiments.

Soft soldering

Soft soldering is the joint-formation method in electronics and plumping industries. On a circuit board, soft soldering connects various components to a bus bar. Soft solders also complete electrical connections on the circuit board. For long copper pipes, soldering them ensures that you create suitable joints. An electric or gas-powered soldering iron acts as a source of melting heat. By adding a flux to the soldered area, the joint becomes stronger. However, the bond formed here is weaker compared to hard soldering.

Hard Soldering

Here, higher temperatures melt the soldering wire. The bond formed is more robust compared to the soft soldered joint. The solder materials used are silver and brass, which are heated until they melt. The source of heat is the electricity or gas torch. Even though the melting temperature is high, it does not melt parent metal. The workpiece should be clean before soldering to form a perfect bond. In some cases, the fluxing of the soldered joint prevents contamination by the oxides. The soldering flux also helps the solder to flow smoothly.

Types of soldering equipment

For joining electronic parts, a soldering iron melts the solder bonding them. The soldering irons have different electrical power rating. Those that are rated higher take a shorter time to heat the solder wire. A soldering gun is a perfect choice for joining a larger workpiece together. A soldering torch is a solution to projects with higher heat requirements

FAQs

What is The Difference between Welding and Brazing?

The following table shows the differences between welding and brazing.

Welding

Brazing

1. Welded joints are most reliable and thus bear more loads compared to base metals.
2. Brazed joints are weaker than welded joints. They withstand considerate loads compared to parent metals.
3. The workpiece heats up until it melts for a joint to form.
4. Workpiece does not melt, molten filler

• joins it together by capillary action.

1. in most cases welded joints require

• activities like grinding.

1. The brazed joints are softer and do not require finishing activities like grinding.

Is Welding Stronger than Brazing

The following are the reasons why welding a joint is more durable than brazing it.

Welding is a high heat process where the parent metal melts fuses together. The bond formed here is more potent than that created by brazing. The mechanical properties of the welded joint may change in most cases. It improves the bonding strength of the fused materials. Brazing depends on the capillary action of the molten filler materials. The filler materials don’t bond completely with base metals in brazing compared to brazing.

Are Soldering and Brazing the Same?

The following are the differences between soldering and brazing.

Soldering

Brazing

1. It creates a weaker joint on the base metals compared to brazing.
2. Brazing a joint makes it more robust than soldering it.
3. Low temperatures of below 450 degrees Celsius melt the solder.
4. Here, filler material melts at temperatures above 450 degrees Celsius.
5. The workpiece does not require prior heating.
6. The workpiece requires preheating before brazing it.
7. High pressure and temperature affect the joints formed
8. Joints are not affected by high temperatures and pressure.

Can I Use a Solder to Weld?

Soldering and welding are two different metal joining techniques. Solder cannot be used to weld because it melts at low temperatures. A welding filler and parent metal material require high heat to melt—the molten metals bond after cooling to form a joint. Contrary to welding, in soldering joints are formed by capillary action. To weld a workpiece, base metals must melt. But, soldering does not require the parent materials to melt before bonding.

What are the advantages of brazing?

The following are some of the advantages of brazing metals.

1. Brazing joins both similar and dissimilar metals with different thicknesses.
2. Brazed joints are more durable than the base metals thus can withstand more weights.
3. In most cases, the joints formed by brazing don’t require finishing activities like grinding.
4. The base metal doesn’t melt; thus, metallurgical damages may not occur.
5. Less heat is required to get the job done than in melting.
6. Well brazed joints are not affected by high temperatures and pressure.

Can the welding rods be used for brazing?

The rule of thumb says No! Welding rods cannot do brazing. The temperatures for welding are higher compared to those for brazing. The heat supplied to weld a joint must melt the welding rod and parent metal. The molten mixture then cools down, making a joint.

On the contrary, brazing heat only melts the filler but not the base metal. The principle of bond formation is by capillary action in brazing. It is not the case as in welding. Additionally, the welding sticks have flux to reduce contamination and oxidation. The brazing heat set this flux into complete burning.

Conclusion

Now by reading through this article, can you make your own choice? The answer should be yes. From this write-up, there is a clear distinction between welding, soldering, and brazing. You can make the right choice among them based on your application. I have also addressed the commonly asked question concerning the topic. The answers to these questions are elaborate and very clear. This article gives the best guideline about the subject.