Introduction
Introduction
Introduction
Rotary Friction Welding
Rotary Friction Welding
Overlay
Experiment
Simulation
Process definition:
Rotary Friction welding (RFW) is a solid-state welding process where two or more parts are axially pressed onto each other under high relative rotational movement. The thereby induced frictional heat plasticizes the material and results into an axial shortening and extrusion of a weld flash. Once the plastification is sufficient the rotational movement is stopped while the force is maintained or increased which forms a solid bond between the parts.
Applications:
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axial joints between arbitrary shaft, disk, tube or bar components
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material combinations between most metallic alloys see matrix below
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established process in almost all industrial sectors, in particular automotive industry
Friction Welding Applications
Turbocharger
Trailer axle
Piston Head
Gear shaft
Advantages:
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many material combinations weldable
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comparatively small heat-affected zone (HAZ)
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fine-grain forged structure
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welding without filler material and shielding gas
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low weld times necessary
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low distortion of the weld parts
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very high static/dynamic strength of the weld, mostly higher than the base materials
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no joint surface preparation necessary
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very low requirements on weld parts (e.g. cleanliness, shape accuracy, etc.)
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very suitable process for automation and mass production
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very good process monitoring capabilities
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no emissions, no splatter
Simulation of Rotary Friction Welding
Joint-zone state-variables plot
With the aid of the process simulation a detailed analysis of the joint properties is possible. In the below picture the state variables pressure, temperature and deformation along the joint zone of a Ø10 mm full shaft friction weld are displayed over the time of the process. The shape of the curves depicts that the material points of the final joint originated from the inner of the shaft. It is nicely seen that the state variables are not homogeneous along the cross section of the weld. The simulation enables the analysis of local properties within the joint and assists process understanding on a much higher level than only by experimental analysis.
Material condition plots
Friction welding resembles a very distinct thermo-mechanical treatment of the involved materials. With the aid of the simulation the history of temperature, plastic deformation rate and von-Mises stresses of each material point of the weld partners can be calculated. Below a statistical evaluation of a typical friction weld is displayed. The color depicts the relative occurrence of thermo-mechanical treatment conditions. Such plots help to understand the mechanical processing modes of friction welds and are a vivid tool for assessment of the metallurgical joint zone properties.
