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FSW, a green welding technology

Today, the environmental issue is fully linked to industry. Why? Because of the contamination caused by these industrial activities on the environment. In the context of Company Social Responsibility – CSR, large companies are now committed to integrate engagements in favour of environmentally friendly economic development into their global strategy. In this eco-responsible approach, the industry optimizes its processes to reduce its consumption of energy and resources.

Industrial welding has progressed: now, new technologies allow to guarantee safety and ecology. Friction Stir Welding (FSW) is an ecological and innovative process that allows solid state joining of heterogeneous alloys. So why is FSW called a green welding process? And how does this technology meet your environmental commitments?

defects in friction stir welding

Friction Stir Welding is a green technology

Is there an environmentally friendly welding technique?

Industrial welding gathers different welding techniques. It can be divided into 2 main blocks: fusion processes and solid-state processes.

Welding processes are often considered controversial because of their environmental impact.

Indeed, conventional fusion welding processes (MIG, TIG, laser) require the use of gas. The very high temperatures required for fusion also generate harmful fumes and consume a lot of energy.

Also, in some cases a filler metal is used to join the parts. This consumable has a strong impact on the life cycle analysis of the final product. In addition, solvents are sometimes used to clean the parts. These products, burned during fusion welding, increase the impact on the environment.

So which welding process is considered environmentally friendly? FSW is a cold-welding process, in the solid state, without gas emissions or material input. Compared to fusion welding, the FSW process is more environmentally friendly and guarantees greater safety for the workers. This “clean” welding technology replaces favourably the traditional assembly processes (riveting, bonding, arc welding, MIG, TIG, laser welding). 

FSW, a green process to combine high performance welding technology and environmental protection

FSW is a breaking technology, appreciated for its numerous technical qualities:

  • It preserves the mechanical characteristics of the welded metals.
  • It allows the joining of all aluminium alloys and also heterogeneous materials.
  • It ensures a remarkable watertightness and pressure resistance.
  • It removes any potential defects related to conventional welding processes (corrosion, ferrous pollution, deformation of parts, roaching defects, etc.).

Friction stir welding is an attractive technology because it’s both, energy saving and environmentally friendly.

Indeed, it’s a green process that does not emit smokes or other projections and does not produce any noise. As it does not require any preparation of the surface to be welded, it does not involve any prior stripping.

Moreover, the main advantage of FSW is that it’s a “cold” welding, more exactly in a pasty state. The weld is made only by mechanical deformation through friction.

This process doesn’t involve melting or adding material and it doesn’t use toxic gases, UV radiation or electromagnetic fields.

Additionally, friction stir welding of aluminium parts requires low power consumption. According to the work of Auguste Sallen and Olivier Kerbrat of the Ecole Normale Supérieur of Rennes, a CNC machine equipped with a welding head consumes between 7 and 11 KW depending on the materials and thicknesses welded.

green technology

The FSW Stirweld solution for an even more ecological approach

Since 1995, the friction stir welding process has been reserved for high value-added applications. Indeed, the manufacture of dedicated FSW machines represents an expensive investment. In 2015, this patent from TWI (The Welding Institute), a research and technological organization specialized in welding, fell into the public domain. T Therefore, the use of friction stir welding could be extended more widely in the industry.

Stirweld’s FSW head permits Friction Stir Welding from existing CNC Machine Tools. The welding head is easily integrated on a machining center, which SMEs are most often already equipped with. Thanks to our solution, this breakthrough technology becomes accessible, and our customers can benefit from an ecological and economical welding technology. 

Compared to the design of special FSW machines or FSW robots, the manufacture of a welding head offers a considerable financial advantage. An advantage of the FSW head: it is universal and therefore can be mounted on any CNC machine. This means that companies do not have to invest in new complex and energy-consuming machines whose manufacture has an environmental impact. The equipment of FSW welding heads is part of a sustainable development approach. Our customers can thus redirect their manufacturing processes to be more ecological and comply with new environmental regulations.

With this friction stir welding head for CNC, parts can be welded and machined on the same machine. This process is suitable for parts of all sizes. Welds less than 10 mm thick require a single pass, which is the case for many industrial applications. Also, this FSW solution requires a single consumable, the FSW tool, a very simple and inexpensive steel pin that provides up to 2,000 m of welding before being replaced. In addition to time and cost savings, Stirweld’s solution permits energy and resource savings.

Welding by FSW with Stirweld head reduces the impact on the environment while ensuring identical performances to a special FSW machine. Stirweld supports its customers throughout the whole industrialization period of the FSW process and makes you benefit from the technical and ecological advantages of friction stir welding.

friction stir welding machine

The Stirweld FSW head manufactured with respect for the environment

Welding processes are highly regulated. Friction Stir Welding is governed by the ISO 25239 standard throughout the industrial process, from design to quality control. Beyond the respect of this welding standard, Stirweld has undertaken the implementation of an environmental management process based on the 14001 and 26000 standards.

Our company is engaged in supporting regional development by encouraging the participation of local suppliers. It therefore limits the impact on the environment of the manufacture of FSW welding heads.

Stirweld selects products and raw materials necessary to manufacture its FSW solutions by taking in consideration the environmental impact of the components. Our conception teams have followed a training in eco-design to make them aware of the analysis of the life cycle of a product. Our design office is continuously looking for solutions to reduce the impact of our products during the manufacturing, use and reprocessing phases.

Finally, Stirweld ensures the recycling of the aluminium resulting from the welding tests for our customers, with local partners.

Friction Stir Welding, a technology for joining renewable materials

The invention of FSW has made it possible to join materials that were previously considered difficult to weld or even un-weldable, such as certain high-performance aluminium alloys. The process consists in welding in solid phase, the thermal impact, and the degradation of the basic mechanical properties of the materials are extremely limited.

Friction stir welding can be used to weld different types of materials, the most common being aluminium and copper. 

FSW permits the welding of dissimilar materials at significant speeds. And it can be applied to thicker materials.

Aluminium, a recyclable and light material 

Aluminium is a great solution to reduce our GHG emissions (greenhouse gases). Its recyclability is a major advantage for the preservation of the environment and limits the reduction of natural resources. It’s indeed a 100% recyclable metal without any loss of its properties. By recycling it, the energy required to produce pure aluminium from bauxite is reduced by about 95%. Aluminium recycling contributes to the reduction of waste. Known as a green metal, aluminium plays an essential role in the energy transition.

Aluminum is one of the lightest metals. It permits the design of vehicles that are lighter and therefore consume less energy. It’s also an essential material for producing solar panels and wind turbines.

In addition, aluminium is a difficult material to weld. Friction stir welding is a green process perfectly adapted to the fast and resistant assembly of all its alloys. Stirweld’s technology allows to keep the mechanical properties of aluminium with an excellent joint efficiency coefficient (over 70%). It permits to reduce the post-weld defect rate and ensures a perfect repeatability. It also offers the possibility to weld high performance aluminium alloys such as AA2024-T3 or AA2219-T8. 

Aluminium is increasingly used today and represents the second most exploited metal after steel. Beyond the recyclability of aluminium, this metal is particularly appreciated for its lightness, malleability, and thermal conductivity. And FSW is the green technology for aluminium assembly.


Copper, an ecological material

Friction stir welding is also applicable to copper, which also has many ecological advantages. Copper has the same qualities as aluminium in terms of sustainable development.

It’s fully recyclable into other copper or alloy products.

This metal is particularly appreciated for its ability to radiate heat. Thanks to its ability to absorb the energy transmitted by the sun, it’s used in the design of photovoltaic panels.

To conduct energy, metals generate heat. Copper is the metal with the best electrical conductivity, after silver. This material is also appreciated for its flexibility.


FSW technology for more ecological industries

Friction stir welding is now mature and fully industrialized. The risk of defects is very low, and it ensures a high degree of reproducibility. This green technology of aluminium assembly is now adopted by industries looking for a combination of high technicality and sustainable development.  It’s now used in many industrial sectors such as transport (e-mobility, aeronautics, space, rail and naval) and renewable energies (solar panels, wind turbines and nuclear).

More eco-friendly transports

Road transport is one of the main sources of greenhouse gas emissions worldwide, the main cause of global warming.The transportation industry must respond to environmental challenges by offering more fuel-efficient vehicles, the main parameter being vehicle weight. This means designing lighter vehicles to reduce energy consumption and emissions. Lightening involves reducing the weight of vehicles while guaranteeing strength and safety. Until now, lightweighting of structures and vehicle bodies has become more widespread thanks to FSW welding of aluminium parts: aluminium foundry heat sinks, battery boxes, rims, etc. Thus, electric cars were the first vehicles to benefit from this breakthrough technology.

Cooling fins on the electronic box

FSW welds to increase thermal conductivity

The substitution of steel sheet for aluminium sheet permits a significant decrease in vehicle weight. The body sheet is not the only field of aluminium application in the automotive. This light and resistant metal is also used for rims, radiators, cylinder heads, etc. Car manufacturers are thus promoting FSW welding of parts for electric and hybrid vehicles.

Friction Stir Welding is also involved in tank manufacturing (cryogenic or not) for trucks or buses running today on natural gas, tomorrow on biogas and hydrogen.

Renewable energies

The wind industry has also adopted FSW for aluminium parts. Friction stir welding is the favoured technology for large, lightweight components such as wind turbine nacelles and blades. Turbines also require efficient and durable parts.

The FSW process is used in the manufacture of solar panels for aluminium liquid cold plates assembly. It is also used for frames and inverters.

Finally, in the nuclear field, FSW welding of copper parts has enabled the development of parameters for serial production.

thermal management

FSW welded aluminum liquid cold plate

Friction Stir Welding: an eco-friendly joining technology

Friction stir welding is a mature technology for the assembly of parts with low melting point such as aluminium. This breaking technology permits, thanks to a rotating pin, to penetrate the material and to mix the materials to be welded in a “pasty” state.

FSW is a key technology in reducing your impact on the environment, improving the quality and reliability of your welds. This eco-friendly welding technology is qualified for many applications in the transportation, space, and energy industries. Valeo, recognized worldwide as one of the largest automotive OEMs, was among the first to study the feasibility of FSW. The reason is obvious: Friction Stir Welding permits the welding of aluminium die casting, an aluminium alloy that is used extensively in the manufacture of automotive parts. Airbus, the aeronautics giant, has also been convinced by FSW technology. Indeed, with this new welding process, Airbus is working to reduce the thickness of the structure of its aircraft. As for Ariane Group, FSW has emerged as the technology that permits them to weld their launchers with a guaranteed quality. Why? Because with FSW, the mechanical properties of the welded materials are preserved even when they are exposed to strong temperature differences.

Stirweld supports its customers in the implementation and optimization of their FSW welding process with the objective of industrialization and sustainable development.

Contact FSW experts

If you want to integrate our FSW solution to your machining centre, please do not hesitate to contact our experts.