What is Friction Welding?
The friction welding process is a mechanical welding method that allows the assembly of two metal pieces in a plastic state. This technique involves generating friction through the linear or rotational movement of one piece or tool against one or more other pieces. This friction produces intense heat at the interface of the two pieces, softening the metal until it becomes plastic. Then, by applying force and maintaining this pressure, the pieces deform and fit perfectly until they are welded together during the cooling process. There are different types of friction welding.
ROTARY FRICTION WELDING (RFW)
In rotary friction welding processes, two pieces are held facing each other. One of the pieces is in rotation while the other remains stationary. Several variations exist depending on how the rotating piece is driven. Once the pre-determined rotation speed is reached, pressure is applied to bring the pieces into contact and assemble them. It is the combination of compression force and high rotation speed that causes self-heating and welding to occur.
In the inertia friction welding variant, the piece is fixed to an inertia flywheel to store the kinetic energy provided by the machine. Once the predetermined rotation speed is reached, the piece is released and continues to rotate due to inertia.
Inertia friction welding
In direct drive friction welding, the piece is rotated or translated directly by the machine. The variation of torque and motor speed enables welding.
Evolution of temperature during the direct drive friction process
LINEAR FRICTION WELDING (LFW)
In linear friction welding, the first piece remains fixed while the second executes small back-and-forth movements. Similar to friction stir welding, this movement generates friction, thus increasing the temperature of the materials. Applying force ensures the formation of the welded joint.
Evolution of temperature during the linear friction welding process
FRICTION STIR SPOT WELDING (FSSW)
Friction stir spot welding involves assembling two pieces arranged to be glued together and held by a clamping system. A specific tool creates a mixing point by friction: the pin (lower part of the tool) increases the temperature of the metal until it becomes plastic, allowing it to be mixed and welded, while the shoulder (upper part) keeps the metal in a plastic state and prevents it from flowing out. Once the mixing point is achieved, the tool is lifted, and the piece can be removed or moved.
Evolution of temperature during the friction stir spot welding process
Benefits of Friction Welding
- Fast assembly speed: Friction welding allows for forming the welded joint in one go, making it faster compared to other processes that require progressive fusion.
- Reproducibility and automation: This type of process is easily reproducible and can be automated, ensuring a consistent level of welded joint quality.
- Crack resistance: The thermomechanical stresses induced by friction welding help limit cracks and resistance issues in assemblies.
- Assembly of different materials: Solid-state welding processes like friction welding enable the assembly of pieces made of different materials (e.g., copper + aluminum, steel + aluminum) since they have fewer metallurgical constraints than fusion welding processes.
- Welding possibilities for sensitive alloys: This type of process allows for welding certain materials that cannot be welded using conventional welding methods.
- Cost reduction and better health: Friction welding is generally less expensive and healthier as it does not require the addition of material and produces little light or fumes.
Due to these advantages, friction welding is increasingly used in various industries such as automotive, aerospace, naval, and space, especially for manufacturing lightweight components.
Benefits of Predictive Simulation
Numerical simulation offers numerous advantages regarding your welding process, allowing you to predict the behavior and thermomechanical properties of your assembly. With our software, you can:
- Study solid-state metallurgy in each area of your welding process.
- Control the temperature evolution, HAZ (Heat-Affected Zone), melted zone, etc.
- Anticipate deformations, residual stresses, and welding-related defects, such as burrs and beads.
- Model and include different heat treatments applied to your welded piece to understand their impact on the weld and its properties (residual stress attenuation, hardness, etc.).
- Perform the first mechanical tests numerically to assess the strength of your assembly.
Using predictive simulation, you can gain in-depth insight into your welding process, forecast results, and optimize parameters to achieve high-quality assemblies. This saves time and reduces costs associated with physical testing while improving the reliability and performance of your welds.
TRANSWELD® Features for Friction Welding
- Easy and quick data input: The intuitive and business-oriented interface allows obtaining initial results within minutes.
- Precise configuration of process parameters: You can accurately define component geometry, effort, rotation speed over time, inertia, temperature, etc.
- Friction file import: You can import a friction file for modeling closer to reality.
- 2.5D method for rapid 3D friction stir welding simulation: This method is particularly suitable for rapid 3D friction stir welding modeling.
- Material database: TRANSWELD® includes a material database containing the main grades used by welders, such as steel alloys, stainless steels, Inconel®, TA6V, and aluminum alloys. You can choose a specific material for each piece.
- Adaptive remeshing: The software uses adaptive remeshing to obtain accurate results in the welded area.
- Fine meshing on the joint: You have the option to apply a fine mesh only on the joint to achieve accurate and fast results.
With all these features, TRANSWELD® offers a comprehensive environment for simulating friction welding accurately and efficiently, thus optimizing the process and obtaining high-quality assemblies.
