Friction Stir Welding for high-performance applications

We enable new solutions for demanding applications in challenging environments

Friction stir welding for high-performance applications allows the joining of high-strength and dissimilar materials, ensuring optimal weld properties and consistent quality assurance. Leveraging our expertise and technology, we deliver innovative solutions for complex requirements.

Challenges in high-performance applications

When fusion welding processes reach their limits

Materials used in the energy sector and in high-performance applications often exhibit limited weldability and require the use of expensive welding consumables. Conventional fusion welding processes frequently reach their technological limits with these high-strength materials and dissimilar material combinations.

Many components used in high-performance applications (e.g. aircraft, aerospace, energy, defence etc.) are made of high-strength materials, such as high-alloy steels, amorphous metals, austenitic UFG steels, or dissimilar material combinations. These materials are extremely sensitive to high heat input and rapid cooling rates and also exhibit high residual stresses. Possible consequences include microstructural changes in the heat-affected zone, shrinkage stresses, and cracking or embrittlement in the weld. Conventional fusion welding processes offer no or only inadequate solutions for these challenges.

In contrast, friction stir welding is characterized by controlled heat input, in which the material does not melt, and therefore the risk of welding-related defects is significantly reduced. At the same time, very good mechanical properties of the weld joint can be achieved, while the need for rework is minimized.

When weld requirements exceed conventional standards

Demanding operating conditions such as extreme ambient temperatures or corrosive media place particularly high requirements on weld seams. Leak tightness, mechanical properties, and a long service life of the welded joint are key criteria to sustainably prevent consequential damage and costly repairs.

The application areas often place extremely high demands on the resilience and durability of components and their welded joints. Extreme ambient temperatures, high pressures—for example, in deep-sea applications—acidic or otherwise corrosive media such as H₂S or seawater, radioactive radiation, and the transport of hydrogen require welds with excellent mechanical properties and high tightness. Furthermore, a long service life of the joints must be guaranteed, as maintenance, repair, or replacement of the components is often complex and costly due to the frequently difficult access to the installations.

Friction stir welding has proven to be a suitable joining process in this context, enabling the creation of a refined microstructure in the joints. This reduces the likelihood of embrittlement or corrosion while simultaneously ensuring higher weld tightness. Moreover, compared to conventional welding methods, friction stir welding achieves superior mechanical properties, such as increased strength or hardness.

When quality assurance demands exceptional effort

In welding processes that still rely on manual tasks or have to take place under demanding conditions – such as at geographically remote locations – factors like reliable reproducibility in manufacturing or efficient quality assurance are often difficult and costly to implement.

Consistent and effective quality assurance is a central component of any manufacturing process, as it ensures that components reliably meet technical requirements and applicable safety standards. It enables the early detection of errors and minimizes scrap and rework, thereby saving time and costs.

Manufacturing processes with a high proportion of manual steps, in particular, place high demands on permissible reproducibility and the consistent adherence to quality standards, and are therefore often associated with increased effort. Furthermore, some work processes must be carried out in geographically exposed or logistically difficult-to-access regions—for example, on oil rigs or in crisis zones—where working conditions for the personnel are often less than ideal.

Friction stir welding, with its fully automated process, offers a suitable solution in these situations, as it can significantly reduce the deployment of personnel resources in potentially hazardous environments. In addition, integrated sensors and data analysis enable seamless quality monitoring and continuous in-line monitoring.

When economic efficiency and sustainability must align

Sustainable production is becoming increasingly important today, as it is a key prerequisite for ensuring a livable environment for future generations. At the same time, it is essential to design production processes to be cost-efficient to remain competitive in the long term.

High energy consumption, the use of filler materials, and extensive rework in conventional welding processes—especially with demanding materials and applications—lead to increased costs, higher resource consumption, and a poor CO₂ balance. Furthermore, social aspects must also be considered, such as the stringent health and safety requirements for welders. Against this backdrop, the transition to more sustainable and cost-efficient methods is often challenging.

Friction stir welding offers significant advantages here, as many of these factors can be reduced or completely eliminated. The single-pass process enables the creation of a continuous weld seam in just one welding operation, resulting in shorter cycle times and thus lower energy consumption and costs. Moreover, the elimination of filler materials, reduced scrap, and significantly lower noise and welding fume emissions contribute to a substantially improved CO₂ balance and increased occupational safety. At the same time, this also results in significant economic benefits.

Our solutions and strengths

Optimal mechanical performance for high-strength and dissimilar materials

Due to the nature of the process, friction stir welding produces a refined microstructure in the welded joint. This results in excellent mechanical properties for joints made from high-strength materials such as pipeline steels, stainless steels, nickel-based alloys, copper and copper alloys, as well as dissimilar material combinations.

The mechanical properties of different steel grades and nickel-based alloys are significantly influenced by the respective welding conditions. Excessive heat input or excessively rapid cooling can lead to variations in hardness, microstructure inhomogeneities, and cracking. Friction stir welding (FSW) operates at low process temperatures, thus enabling targeted grain refinement, particularly in high-strength steels, while preserving the precipitation state of, for example, nickel-based alloys.

In contrast, the high thermal conductivity of materials such as copper makes joining with conventional fusion welding processes difficult. Typical problems such as weld defects, porosity, and grain coarsening often result in reduced mechanical properties and lower electrical conductivity. Friction stir welding operates at only 50–80% of the melting temperature, thereby achieving a flawless weld quality with a refined microstructure. However, the industrial applications of FSW for copper are often limited by low welding speeds and long cycle times. We offer a comprehensive solution comprising welding tools and machines that enables the joining of pure copper and copper alloys with thick walls, and can also be extended to incompatible combinations with steel and aluminum. Welding speeds of up to 2 m/min can be achieved with optimal quality in butt and lap joints.

Consistent weld quality ensured by hybrid parameter control

The machine control allows the use of a combination of temperature and torque control, ensuring consistent weld quality and enabling precise adjustment of the mechanical properties.

To guarantee the required weld quality, we offer torque and temperature control. Depending on the material, the resulting microstructure of the weld seam can be directly determined. This not only allows for the adjustment of mechanical properties according to your requirements but also guarantees seamless quality assurance. The temperature control uses continuous monitoring of the welding parameters based on the set temperature. This is integrated into the machine using a combination of different temperature measuring devices. This compensates for process fluctuations, prevents material damage, and ensures reproducible, high-strength welds.

Fully automated systems for continuous quality control and in-line monitoring

Fully automated FSW machines are designed for a CNC-controlled, reproducible welding process. The use of clearly defined control variables for process management—such as axial force, position, rotational speed, torque, and temperature—minimizes the influence of operator skill. Continuous data acquisition provides the foundation for qualified processes, traceable quality control, and stable multi-pass or continuous operation.

Fully automated FSW machines are designed as CNC-guided systems with clearly defined process parameters. The welding process is controlled and continuously monitored via the key parameters of axial force, position/rotational speed, torque, and temperature. This ensures reproducible process conditions, minimizing the operator's influence on the welding result. The process principle is insensitive to typical external disturbances and operates without arcing, spatter, or welding-related emissions. Common surface contaminants can be tolerated within defined limits, and the requirements for the precise positioning of the components are lower compared to high-energy processes, thus reducing setup and preparation time. Positioning and weld initiation are reproducible and require no manual adjustments.

The welding process requires no manual intervention near the tool during operation and is organized into clearly defined, safe operating modes. Non-productive time is reduced, among other things, by eliminating tack welding and filler material. Tool life can be estimated based on monitored process parameters and integrated into maintenance planning. The continuous recording and storage of all relevant process variables forms the basis for digital weld documentation and supports qualified processes in accordance with current WPS and WPQR requirements. This allows the scope of downstream inspections to be reduced and focused specifically on process-critical areas.

The process-relevant know-how is stored in the machine and control system, while the operator primarily performs monitoring and organizational tasks. This reduces dependence on highly qualified welding personnel, simplifies deployment planning, and supports stable operation in multi-shift or continuous operation.

With FSW we combine economic efficiency and sustainability

High welding speeds, minimal pre- and post-processing, and the autogenous process (i.e., avoiding welding filler materials) guarantee economical and sustainable production.

Friction stir welding offers significant sustainability advantages compared to conventional welding processes. These include considerably lower energy consumption, reduced need for pre- and post-treatment (e.g., heat treatments or surface sealing), more efficient material usage, and a lower scrap rate. Furthermore, it eliminates the need for hazardous filler materials, while significantly reducing noise and welding fume emissions and extending the service life of the welds.

These factors result in a significantly improved CO₂ balance and increased occupational safety. At the same time, the reduction in material and energy resources (up to 60% less energy consumption), higher welding speeds, a high degree of automation, and the resulting process stability also lead to cost savings and thus significant economic advantages. Friction stir welding therefore represents an attractive and future-oriented alternative for a wide range of welding applications.

Friction Stir Welding of Steel

Friction Stir Welding of Copper

Circumferential FSW of Steel

Our products and services

Turnkey friction stir welding systems

Complete solutions from a single source: from machine delivery and automation to integration into your production line. Our systems are immediately ready for series production, reliable, and cost-efficient – including QA software, clamping technology, and the welding process.

Everything from a single source

Our FSW machines are far more than just welding systems – they are fully integrated, customer-specific production solutions. As turnkey systems, they encompass machines, clamping technology, tooling, process control, and quality assurance from a single source. The machine range extends from 3-axis machines for linear and 2D contoured welding applications to systems for pipe welding processes in 1G to 5G layers, including orbital designs. The systems are complemented by specially developed clamping and fixture concepts that securely, flexibly, and reproducibly fix components, even under high process forces and with complex geometries.

Equally crucial is the design of the FSW process control as a complete system. Based on this, customized tools and optimized process parameters are used, enabling consistent weld quality with predictable tool life. This results in stable and controlled processes for producing durable joints with short cycle times and downtime. The result is a range of complete, production-ready solutions that integrate seamlessly into existing manufacturing environments and can be used productively from the outset.

Our systems come standard with STIRlytics quality software. This enables continuous monitoring of all relevant welding parameters, analysis of process data, and early detection of deviations and optimization potential. Every manufacturing step is fully documented, ensuring complete traceability of every single weld. This guarantees reproducible quality, reduces scrap, and minimizes rework. At the same time, your series production becomes predictable, efficient, and reliable, without compromising performance or safety.

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MaXstir FSW tools

Tools that are durable, precise, and perfectly tailored to your components – optimized for maximum welding speeds, minimal scrap rates, and consistently reproducible quality.

Precision driven by passion

We develop and manufacture customized FSW tools that are perfectly tailored to your components and manufacturing processes. Each tool is produced with the highest precision, carefully selected materials, standardized heat treatments, and sound design. This ensures maximum process reliability, consistent weld quality, and a long tool life – even for demanding production runs and high cycle rates. Our in-house qualification program guarantees that every tool meets the rigors of real-world applications. The result is tools that are reliable, repeatable, and proven – an essential building block for efficient and error-free series production.

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Services from A to Z

Stirtec offers everything related to Friction Stir Welding – from design and qualification to prototyping, training, and comprehensive service & support, both remotely and on-site. We accompany you from the initial idea to full-scale production – efficiently, safely, and cost-effectively.

We support you through every project phase

We provide comprehensive support throughout all project phases – from initial concept development and feasibility and sampling projects to ongoing series production. We ensure that your FSW processes run efficiently, reliably, and reproducibly from the outset. Our service package includes weld qualification and welding procedure tests according to ISO standards, practical FSW training courses and workshops for your employees, and comprehensive service and support. This guarantees the quality, predictability, and efficiency of your manufacturing, minimizes downtime, and reliably supports your projects – from the initial concept to productive series operation.

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sales@stirtec.at

+43 316 30 98 43