How Does Friction Stir Welding Work? (Full Guide)

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Last Updated on August 15, 2021 by weldinghubs

Friction stir welding is a process that joins two pieces of metal without the use of heat or pressure.

It’s an innovative, cost-effective way to join metals and it can be used on materials like titanium, nickel alloys, super alloys, aluminum, and copper alloys.

FSW is a solid-state joining process that uses frictional heat and pressure to create strong bonds between metal sheets without melting them.

It’s an alternative to the traditional arc-welding methods such as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and shielded metal arc welding (SMAW).

FSW has been used in aerospace applications since the 1990s and was approved by NASA in 2005 for use on space shuttle external tank components.

This article will give you the basics about how friction stir welding works, so you can get started with this new technique in your industry today.

Do you want to know more about this revolutionary process? Keep reading! We’ll tell you everything we know about How Does Friction Stir Welding Works.

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What is Friction Stir Welding?

Friction Stir Welding is a rather new joining process that, unlike traditional welding, it does not require high temperatures to work. During the FSW process, a special tool -ideally made up of an outside layer of non-ferrous metal and an inner layer called “filler metal” is driven back and forth through the interface of two parts. The friction creates enough heat to soften the metal pieces at their joint so they can be welded together without melting them or adding heat from elsewhere.

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What is the Process of Friction Stir Welding?

FSW is a way of joining two things together.

It works by using a special tool that rotates the metal and then heats it up. This makes the metal melt into one thing.

The tool is specially designed for friction stir welding, so it can be used to weld two different types of joints: lap joints and butt joints.

The tool has several parts. One part is the shoulder, which goes on top of the metal pieces and makes them hot.

First, you need to pin down the pieces that are being welded together with the pin part of the tool and then rotate them with the shoulder part until they are hot enough – this will take about half a minute or so.

Then you move across what’s been heated up since the heat makes particles from both parts stick together to make one piece – this is why it’s called friction stir welding.

To weld two different pieces together you can choose between a lap joint and a butt joint. For a lap joint, all you have to do is insert the pin part of the tool into both parts that are being joined until they are in position and then rotate while heating up with the shoulder part – don’t forget about the bit between joining and rotating, the pin! The tool will both join and rotate once you put it into position.

But if you are welding a butt joint all you need to do is to insert the pin part of the tool into one of the ends first, then rotate while heating up until everything is hot enough and finally move across with the tool, pinning down both parts all the time until it’s complete. When you are done with welding, wash off any oxidation from the surface of the weld with WD40.

It is important to be careful when doing friction stir welding as it tends to be a bit tricky – but once you get the hang of it, you’ll be as skilled an engineer as it’s possible to get.

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What is the difference between Friction stir welding and friction welding?

There are two methods of welding that use friction to create heat.

One is friction welding. With this method, one piece of metal can be in contact with another, and the heat from the movement will cause them to fuse together. There are some problems with this method though. It is difficult to move the pieces apart because it has to be done quickly, and they can only move along a straight line so they have to stay in that position while doing the welding.

On the other hand, friction stir welding solves both of these problems because it does not require any movement at all before it starts working (the pieces just stay put), and it creates strong joints without any HAZs (when you weld two pieces together).

Both FSW and FRW are good at making strong joints.

FRW can join two pieces together, even if the pieces are different materials. FSW is just for joining metal like aluminum together.

FRW doesn’t have any hot spots which make the weld stronger, while FSW does have hot spots that might make it weaker than an FRW weld.

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Benefits of using the Friction Stir welding method

Below are the benefits of friction stir welding that cannot be gained with other methods.

  1. FSW is a solid-state welding process, which means it is an easy way to make things that don’t fit together and there is less energy needed.
  2. There is no need for solvents or shielding gas for aluminum alloys, which makes friction stir welding an environmentally friendly process.
  3. This process does not produce any fumes or spatter or radiation, and there are no solvents required for degreasing and the waste produced is minimal with this type of weld method.
  4. Less fuel consumption can be needed in airplanes, ships, and automobiles where friction stir welding has been used before since it uses machinery that can be automated easily with a low need for highly skilled welders to operate the equipment.
  5. This process can be done at any angle, whether linear or not. Other processes might need to be linear, but friction stir welding can still produce a high-quality weld even if it is non-linear.
  6. There are no surface preparation requirements in most cases for friction stir welding, unlike other methods that require much more energy and time investment than this process does.
  7. The process usually does not cause shrinkage of the parts being joined with friction stir welding either which means there will be minimal distortions after joining occurs – something that is common in some other types of welds, especially those using filler material or consumables like flux or shielding gas for aluminum alloys.
  8. You don’t have to worry about microstructural damage in the parts being joined because friction stir welding does not produce any deleterious effects from heat or time, unlike some other processes.
  9. FSW is a way to join many alloys of aluminum that are generally considered non-weldable with other methods like arc or gas metal arc welding.
  10. This process usually does not require special edge preparation in most cases, unlike other types of welds that might need much more energy and time investment than this one since they would need preparation on the edges before joining can take place.
  11. Friction stir welding also doesn’t use a filler material or consumables such as flux for aluminum alloys either which means you will have less wasted materials and there won’t be anything that interferes with the aesthetics of the parts being joined since they don’t need to have holes or grooves in them for filler materials to go into.
  12. There is no distortion in the parts after joining because friction stir welding does not cause shrinkage like some other methods might.
  13. You can do this process without creating porosity, unlike arc and gas metal arc welding which are other types of processes you may consider using for aluminum alloys requiring high toughness bonds.
  14. Friction stir welding can work at any angle, whether linear or non-linear, versus only working on a linear axis when it comes to fusion welds – something that not many welds can say since fusion welds might need a lot of energy, equipment, and time to get the right angle for joining.
  15. The process can join alloys that are not weldable by other processes like fusion welds which make it an excellent choice in many situations where hardware is involved. You may be able to find more out about friction stir welding online as well at Engineering360 or Engineers Edge if you want further details about this welding process.

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What are the Disadvantages of Friction Stir Welding?

FSW is a process that has been used in the manufacturing industry for decades. It’s an innovative and efficient way to join metal sheets together, but it does have some disadvantages.

If you’re considering using this process, here are some of the drawbacks to consider before making your decision.

You’ll want to weigh these factors carefully before deciding on whether or not friction stir welding is right for your company. The advantages may outweigh the disadvantages depending on what you need from your welds.

Let’s start with the disadvantages:

01. It is relatively difficult to learn how to properly use friction stir welding, and this is true of any other form of welding.

The technique requires you to follow precise procedures for storage, preparation, and assembly so that everything goes smoothly during the actual process.

The equipment and various factors involved are all extremely important in ensuring a successful weld.

To be able to properly do this correctly takes time and practice, perhaps more than with other kinds of welds.

If your company can’t afford the training your workers will need or you don’t have the extra time required for enough practice runs before attempting real-world projects then this may not be an ideal option for you.

02. Another disadvantage of using friction stir welding is that it is not necessarily compatible with all materials.

Those that are difficult to work with include those that have high amounts of carbon because when the carbon is exposed to heat it can cause a reaction that will interfere with the welding process.

The process also doesn’t work well on metals like copper and other base metals, as they react poorly to extreme temperatures.

If you only deal with certain types of materials in your industry then this may not be a problem for you; however, if you need welds on a variety of different kinds of metal then friction stir welding might not be ideal for your business needs.

03. Friction stir welding isn’t always very aesthetically pleasing, especially if you’re trying to match colors and create a joining effect that is uniform and appealing.

The lines on the metal created by friction stir welding are obvious, which isn’t ideal if you’re trying to create a seamless look for your materials.

If you have aesthetic concerns in mind then this might be a disadvantage for you.

04. There’s always a risk of cracking with any type of welds, but this happens more often than not when using friction stir welding because it uses low amounts of heat and asks a lot of your materials.

You’ll need to ensure that all your materials are very strong, perhaps even stronger than they would normally need to be in order for them to withstand the pressure put on them during this process. Otherwise, there is a high chance they will crack before being fully welded together.

This is another disadvantage that will affect some industries more than others, such as if you’re trying to create a lighter material or something of the sort.

05. Friction stir welding creates an exit hole on the opposite side from where it was applied, which may be undesirable depending on your business needs.

Depending on what you’re working with and how high quality your product has to be then this could pose a problem for you in your project’s final presentation.

06. You’ll need special equipment in order to carry out friction stir welding projects successfully; however, the advantage of this disadvantage (if you look at it this way) is that it’s a proven form of metal welding and therefore not likely to go out of style anytime soon.

While it may take time and practice to master the art of friction stir welding, you’ll always have access to your equipment in order to do it effectively if you have invested in this type of machinery.

07. Friction stir welding is known for creating bubbles, seams or otherwise imperfections near the welds that are not visible on other kinds of weld projects. That being said, these aren’t usually seen as problems unless you need a seamless appearance from your finished materials.

08. The last disadvantage of using friction stir welding is that since metalwork can be complex sometimes then there’s always the possibility that something could get damaged or lost during transportation to another place before being fully assembled into its intended finished product.

This is a risk that you may or may not have to take, depending on the types of projects you work with and how much they need to be protected throughout the process.

If you only deal with certain materials in your business world then this might not apply to you; however, if these are high-value metals being transported between different places for final assembly then you will want to consider additional security measures during transportation.

Knowing about potential disadvantages can help a business owner make better decisions when it comes to choosing which welding processes would ultimately benefit their particular needs best. There are many factors that go into deciding what method of metalwork is right for any given project or situation, and after considering all the facts and details it’s easy to point to friction stir welding as the most ideal solution in any given case.

I’m sure you’ll agree once you’ve had a chance to read more about how easy it is for anyone with no prior experience or special training to learn how to effectively use friction stir welding in their line of work.

Applications of FSW in various industries

Friction stir welding is used for many things in different industries. It is used for joining aluminum alloys from any series, cast or rolled, or even extruded.

Friction stir welding has the ability to bond aluminum alloys with thicknesses between 3mm and 75mm in just one process, depending on the material, machine power being used as well as stiffness of the structure.

FSW sees a lot of use in shipbuilding, offshore, aerospace, and automotive industries. It can also be applied to electric vehicles and rail transit systems.

In the shipbuilding industry, the friction stir welding process is used in the construction of large ships. In the case of offshore industries, it is necessary to have a stable and robust keel structure for long-term performance, which can only be obtained through an effective combination of structural materials. FSW comes into play by allowing composite building materials such as steel and wood to be easily joined.


Friction Stir Welding is a new metal joining process that joins two pieces of steel, aluminum, or titanium together without external energy input. It has many benefits over traditional welding processes and can be used in industries like construction, aerospace, oil rigging, and more. With all the information we’ve provided you should have an idea of what friction stir welding is and how it works. If you need help deciding if this type of weld would work for your project let us know. We will gladly answer any questions to give you peace of mind about using FSW as a metal joining method for your business needs.


Which materials cannot be friction stir welded?

Contrary to popular belief, not all materials can be welded by a friction welding process. For example, dry bearings and non-forgeable materials cannot because they are too rigid when hot for any deformation of the material to occur.

Which motion between materials in friction stirs welding helps in joining of the metal?

Friction welding has been used for centuries to create durable bonds. The process relies on the induced mechanical motion of friction in order to soften materials and form a viscous bond that can withstand extreme temperatures without damage.

What are the four 4 variants of friction stir welding?

There are several variants of Friction Stir Welding (FSW), including Twin-stir, bobbin stir welding, FSW of steel and titanium.

What are some common applications of friction stir welding?

Friction stir welding is used on a wide range of materials, from shipbuilding and offshore to robotics. These are just some examples where friction stir welding has been an integral part of the manufacturing process for many years.

What is friction stir welding and how is it different from friction welding?

Linear friction welding is a process used to join two metallic parts without melting. Friction stir welding uses rotational shear stresses to create high-quality, low-distortion joints.

What is the limitation of friction stir welding?

This process is slower than many other processes, and it cannot make weld joints with metal deposition. The initial cost of the machine for this welding technique is too high; in addition to being less flexible than manual or arc welder machines.

What is a fusion method in welding?

Fusion welding is a technique for combining two or more materials into one by heating them and allowing the heat to melt together. The process may involve filler material, but can also be done without it depending on what's being welded.

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