What is Fusion Welding? – Basics and Types of This Process

After reading this article, you will be able to define fusion welding, its different types, the application, advantages, and disadvantages of fusion welding.
By
reviewed
Reviewed by
Last updatedLast updated: July 02, 2022
Weld Zone is reader-supported. We may earn a commission through products purchased using links on this page. Learn more about our process here

Welding dates back to 3000 B.C. Egyptians learned the art of welding during the Iron Age. The Egyptians combined two pieces of metal by hammering while under heat until they joined.  However, in 1881 a Russian named Nikolay Benardos invented carbon arc welding.

After several years of technological developments, welding techniques have evolved to more methods that are straightforward. Currently, there are more than ninety different types of welding. These processes continue with more advanced studies in the transport, building, and nuclear industries. So, what is fusion welding?

Basics of Fusion Welding

People often come across the term fusion arc welding but are unaware of its meaning. So, how do we define fusion welding? Fusion welding involves joining two or more objects by heating. When performing fusion welding, one could use filler materials, depending on the work’s nature. Welders do not apply external pressure when joining the parts.

Fusion welding is different from non-fusion welding. Non-fusion welding takes place under low heat intensity. During this process, the base metal does not undergo any melting process. Welders do not use filler materials when performing non-fusion welding. The best examples of non-fusion welding include soldering, pressure, and brazing welding.

What is Fusion Welding? – Basics and Types of This Process

Fusion welding is a process that uses heat to join or fuse two or more materials by heating them to a melting point.

What is Welding?

Before understanding fusion welding definition, it is essential to define the term welding. Welding has become an integral part of the building industry. A recent study by the AWS Trusted Source About AWS | American Welding Society The American Welding Society (AWS) was founded in 1919, as a nonprofit organization with a global mission: advancing the science, technology, and application of welding and allied joining and cutting processes, including brazing, soldering and thermal spraying. www.aws.org (American Welding Society) found that welding affects 50% of the U.S. gross product.  Welding is a manufacturing process that involves joining two or more identical or non-identical parts using heat. The process might include using a filler or not, depending on the nature of the work.

There are two types of welding

  • Fusion welding
  • Solid-state welding

How Does Fusion Welding Work?

According to the original definition, fusion welding involves joining two edges of similar or different materials using heat. The heat melts the two parts that join together as they cool. In some cases, one can use filler material if the gap between the two parts is extensive. The base material undergoes different stages since the heating process develops a heat affected zone Trusted Source What is the 'Heat Affected Zone' in welding and which types of Welding Processes produce less HAZ? | CWB Group The heat affected zone (HAZ) is that area of metal that has not been melted and has undergone changes in properties as a result of being exposed to relatively high temperatures during welding. www.cwbgroup.org within the materials.

Fusion welding takes part when the molten parts of the base material are combined with the molten filler. It involves applying heat to melt the material on the joining zone or develop a joint externally at the weld point. According to various reviews, the Forney Easy Weld 140 MP is the best equipment for performing different types of fusion welding.

Types of Fusion Welding Processes

After finding the full definition of fusion welding, it is crucial to understand fusion welding types. The different types of fusion welding are categorized based on the heat source. below are some of the main types of fusion welding:

Arc Welding

Fusion arc welding is the most common type of fusion welding. Arc welding involves connecting two or more parts using an electric art. The electric arcs produce high levels above 6000 degrees Fahrenheit using the machines like YESWELDER Digital MIG-205DS MIG welder. This feature makes fusion arc welding ideal for joining hard materials. Welders can also perform arc welding underwater. The most common types of arc welding include:

  • Shielded metal arc welding is used for welding ferrous and non-ferrous materials regardless of the position.
  • Tungsten inert gas welding uses non-consumable tungsten to create the arc between the electrode and the base plate. The TIG welders for aluminum use an inert shielding gas to prevent contamination and oxidation.

  • Metal gas arc welding involves the formation of an electric arc between the wire electrode and the material using the MIG welders. The use of shielding gas prevents contamination.
  • Submerged arc welding is the method that involves using flux and a consumable electrode. The flux prevents the sparks and spatters and conducts electricity while in the molten state.
  • Plasma arc welding involves the formation of an electric arc between the nozzle and the electrode. The electric arc ionizes the argon gas found in the chamber.
  • Flux cored arc welding is an alternative to shielded Metal Arc Welding. The whole process involves feeding consumable electrodes with flux using the flux core welders for the thickest metals.

Gas Welding

Some people would refer to it as Oxy-fuel or oxyacetylene welding. This process involves using a blowpipe held in the hand that combines both oxygen and acetylene gas to produce a flare. It is a solvent-based fusion welding that requires a flame to meltdown and connects the surface. Oxygen acts s the primary fuel source for the flame.

This welding type bases its foundation that there must be oxygen to produce fire. The oxygen allows it to create an extremely hot flame that surpasses 4500 degrees Fahrenheit.

High Energy Welding

High energy welding is a type of fusion welding that uses light radiation to produce heat. Welders blast the radiation on the material’s surface, turning them into a molten state. The two pieces will join once they cool down. The two types of high-energy fusion welding include:

Electron Beam Welding

What is Fusion Welding? – Basics and Types of This Process

This high-energy welding uses high-velocity electrons to join two different materials. The process takes place under normal atmospheric pressure, and the electrons produce heat in the material as they enter. The welts are mostly deep and narrow.

Laser Beam Welding

What is Fusion Welding? – Basics and Types of This Process

Laser beam welding utilizes a laser beam as the primary source of heat. The use of the laser beam helps maintain a highly focused energy source that is used to join different metal pieces of plastics. It uses light energy to produce heat. The rig produces dissipated light that warms the surface with every single blast.

Resistance Welding

Resistance welding is one of the fastest fusion welding types. The speed makes it best for use in the automotive industry. Two types of resistance welding include:

Resistance Seam Welding

What is Fusion Welding? – Basics and Types of This Process

Resistance welding working principle

This type of resistance welding involves creating a persistent joint with alternating nuggets. It uses shifting disks to replace the traditional spot welding electrodes as the process goes on.

Resistance Spot Welding

What is Fusion Welding? – Basics and Types of This Process

This form of bonding produces heat across two electrodes and depends on the material’s properties and thickness of the workpiece. Welders confine the voltage to a precise spot as the separate workpieces combine concurrently.

Friction Welding

Friction welding involves the joining of two different materials using mechanical friction. There are numerous procedures to perform mechanical friction on steel, aluminum, and wood. The process is arduous, but the heat produced is enough to soften and join two separate parts as they cool.

Some of the main types of friction welding include:

  • Rotary friction welding
  • Friction stir spot welding
  • Linear friction welding
  • Friction stir welding

During friction welding, one does not require shielding gas, filler, or flux. The process is best for joining light and non-weldable materials such as alloys for aluminum.

Applications of Fusion Welding

Several processes involve the use of fusion welding. Structural engineers use fusion welding when manufacturing large structures such as:

  • Airplanes
  • Bridges
  • Ships
  • Pressure vessels
  • Welded pipes
  • Shielding explosives

Since it produces high heat levels, one can use fusion metals to combine different materials regardless of their thickness. Some of the main applications include:

Joining Metals

Fusion welding involves using high heat levels in joining two or more separate parts.  Unlike soldering, fusion welding melts the base metal and may require a filler material to make a joint. High heat exposure turns the metal part into a molten state. These parts join together to form a weld bead as it cools down. The result is always stronger than the base material.

When joining metals, one may need to exert pressure to make welds with a heat source. When joining two metals, shielding gas helps prevent the filler material or joint from contaminating or oxidizing.

Joining Plastics

Fusion welding is also applicable when joining plastics. Solvent welding uses adhesives instead of heat. Joining plastics using fusion welding takes place in 3 states which include;

  • Preparing the surfaces by cleaning and drying
  • Applying heat and exerting pressure on the molten part.
  • Cool down the molten parts to create a strong bond between the two plastics. The process might require a cooling room. However, this may not be important since the process is also fast.
Experts use low heat levels when joining plastics since they are softer than metals. One can use internal or external forms of heating.

Joining Wood Materials

Welding wood parts also require the generation of heat from mechanical friction. The welders expose the materials to intense pressure followed by a linear friction movement that produces heat to bond the two wooden parts.

The process is quick and does not require nails or adhesive to join the two different parts. It also maintains the original design and provides a stronger final workpiece.

What is Fusion Welding? – Basics and Types of This Process

Wood welding is a novel process of joining wood pieces without using adhesives or any other material.

Two Sides of Fusion Welding

Like any other process, fusion welding comes with a fair share of advantages and disadvantages.

Upsides

First, It is easy to use a filler when the gap between the two parts is large. Fusion does not alter the original shape since no use of external pressure. Also, one does not require to perform edge preparation or design since it may affect heat penetration. In addition, fusion produces a strong joint between the parent materials. This process is quick hence suitable for most industrial processes.

Downsides

As for the downsides, binding two different materials is difficult, especially when two different melting points. Fusion undergoes some levels of degradation and production of remnant stress since it creates the need for fusion and solidification. More so, the heating process alters the structure of the parent material. Finally, the joined part forms the heat-affected zone that most people view as the weakest point in the structure.

Below is the table of the main advantages and disadvantages of fusion welding.

Pros

Cons

  • One can use a filler material to join two wide parts
  • The original shape does not matter as it requires no pressure
  • Edge preparation and design is not necessary and may affect the heat penetration
  • The welded joint is stronger
  • It is a quick and simple process hence suitable for most industrial processes
  • Difficult to apply when binding two materials that have varying meting points
  • The need for fusion and solidification creates a certain level of stress and degradation on the welded part
  • The process alters the original structure of the parent material
  • The joined parts are the heat-affected zone and are considered the weakest points in the whole structure

 

FAQs

What is fusion welding’s simple definition?

Fusion welding is a process that involves the use of heat to combine two or more materials. It may require a filler material depending on the nature of the work. It does not need pressure except for resistance welding.

What are the basic principles of fusion arc welding?

Fusion arc welding uses sufficient heat from a heat source to convert the joining parts into a molten state. Gas and electricity are the most common types of heat sources.

What is the key difference between fusion and non-fusion welding?

Fusion welding requires high heat intensities that melt the parent material, while non-fusion welding does not involve melting the parent materials hence fewer heat intensities. In addition, fusion welding may require fillers while non-fusion welding does not.

Final Thoughts

Fusion welding is a common type applied in various industrial and building processes. This process involves using heat to melt and join different parent materials and may require filler material. As said earlier, fusion welding creates a strong bond between the joined parts. The factors that may affect the quality of the fused joint are the size, shape, and relative position of the molten pool, the contact pressure exerted on the workpiece surface, and the cooling methods employed.

One of the benefits of fusion welding is that it can be done at a low cost, making it a reliable option for many industries. The disadvantages of fusion welding are related to weld quality, weld appearance, and the weldability of metals.

We hope now you can answer the question ‘what is fusion welding?’ with the help of this article!

References

1.
About AWS | American Welding Society
The American Welding Society (AWS) was founded in 1919, as a nonprofit organization with a global mission: advancing the science, technology, and application of welding and allied joining and cutting processes, including brazing, soldering and thermal spraying.
2.
What is the 'Heat Affected Zone' in welding and which types of Welding Processes produce less HAZ? | CWB Group
The heat affected zone (HAZ) is that area of metal that has not been melted and has undergone changes in properties as a result of being exposed to relatively high temperatures during welding.
Leave a Reply

Your email address will not be published.