29-03-2011, 09:46 AM
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WHAT IS FRICTION STIR WELDING:-
Friction stir welding (FSW) is a highly important and recently developed joining technology that produces a solid phase bond. It uses a rotating tool to generate frictional heat that causes material of the components to be welded to soften without reaching the melting point and allows the tool to move along the weld line. Plasticized material is transferred from the leading edge to trailing edge of the tool probe, leaving a solid phase bond between the two parts.
Friction welding is a process in which the heat for welding is produced by direct conversion of mechanical energy to thermal energy, at the interface between the workpieces. The thermal energy developed from the interaction of two surfaces, rubbed together under pressure and relative motion, can be harnessed to provide conditions suitable for welding and material processing. The friction welding process has, to a large extent, been restricted to round, square, or rectangular bars for the last five decades since its inception.
Friction Stir Welding - Applications Shipbuilding and marine industries
The shipbuilding and marine industries are two of the first industry sectors which have adopted the process for commercial applications. The process is suitable for the following applications:
Panels
• for decks, sides, bulkheads and floors
• Aluminium extrusions
• Hulls and superstructures
• Helicopter landing platforms
• Marine and transport structures
• Refrigeration plant
Aerospace industry
At present the aerospace industry is welding prototype and production parts by friction stir welding. Opportunities exist to weld skins to spars, ribs, and stringers for use in military and civilian aircraft. The friction stir welding process can therefore be considered for:
• Wings.
• Aviation fuel tanks
• Military and scientific rockets
• Various primary and secondary structural components
Railway industry
The commercial production of high speed trains made from aluminium extrusions which may be joined by friction stir welding has been published. Applications include:
• High speed trains
• Rolling stock of railways, underground carriages, trams
• Railway tankers and goods wagons
• Container bodies
Land transportation
The friction stir welding process is currently being used commercially, and is also being assessed by several automotive companies and suppliers to this industrial sector for its commercial application. Existing and potential applications include:
• Engine and chassis cradles
• Wheel rims
• Truck bodies
• Tail lifts for lorries
• Mobile cranes
• Fuel tankers
• Motorcycle and bicycle frames
Other industry sectors
Friction stir welding can also be considered for:
• Electric motor housings (in production)
• Refrigeration panels
• Cooking equipment and kitchens
• White goods
• Gas tanks and gas cylinders
• Connecting of aluminium or copper coils in rolling mills
• Furniture
• Many other applications
Friction Stir Welding - Process advantages
The process advantages result from the fact that the FSW process (as all friction welding of metals) takes place in the solid phase below the melting point of the materials to be joined. The benefits therefore include the ability to join materials which are difficult to fusion weld, for example 2000 and 7000 aluminium alloys.
• Low distortion, even in long welds
• Excellent mechanical properties as proven by fatigue, tensile and bend tests
• No arc
• No fume
• No porosity
• No spatter
• Low shrinkage
• Can operate in all positions
• Energy efficient
• Non-consumable tool
• No filler wire
• Can weld aluminium and copper of >50mm thickness.
The limitations of the FSW process are being reduced by intensive research and development. However, the main limitations of the FSW process are at present:
• Workpieces must be rigidly clamped
• Keyhole at the end of each weld
• Cannot make joints which required metal deposition (e.g. fillet welds)
WHAT IS FRICTION STIR WELDING:-
Friction stir welding (FSW) is a highly important and recently developed joining technology that produces a solid phase bond. It uses a rotating tool to generate frictional heat that causes material of the components to be welded to soften without reaching the melting point and allows the tool to move along the weld line. Plasticized material is transferred from the leading edge to trailing edge of the tool probe, leaving a solid phase bond between the two parts.
Friction welding is a process in which the heat for welding is produced by direct conversion of mechanical energy to thermal energy, at the interface between the workpieces. The thermal energy developed from the interaction of two surfaces, rubbed together under pressure and relative motion, can be harnessed to provide conditions suitable for welding and material processing. The friction welding process has, to a large extent, been restricted to round, square, or rectangular bars for the last five decades since its inception.
Friction Stir Welding - Applications Shipbuilding and marine industries
The shipbuilding and marine industries are two of the first industry sectors which have adopted the process for commercial applications. The process is suitable for the following applications:
Panels
• for decks, sides, bulkheads and floors
• Aluminium extrusions
• Hulls and superstructures
• Helicopter landing platforms
• Marine and transport structures
• Refrigeration plant
Aerospace industry
At present the aerospace industry is welding prototype and production parts by friction stir welding. Opportunities exist to weld skins to spars, ribs, and stringers for use in military and civilian aircraft. The friction stir welding process can therefore be considered for:
• Wings.
• Aviation fuel tanks
• Military and scientific rockets
• Various primary and secondary structural components
Railway industry
The commercial production of high speed trains made from aluminium extrusions which may be joined by friction stir welding has been published. Applications include:
• High speed trains
• Rolling stock of railways, underground carriages, trams
• Railway tankers and goods wagons
• Container bodies
Land transportation
The friction stir welding process is currently being used commercially, and is also being assessed by several automotive companies and suppliers to this industrial sector for its commercial application. Existing and potential applications include:
• Engine and chassis cradles
• Wheel rims
• Truck bodies
• Tail lifts for lorries
• Mobile cranes
• Fuel tankers
• Motorcycle and bicycle frames
Other industry sectors
Friction stir welding can also be considered for:
• Electric motor housings (in production)
• Refrigeration panels
• Cooking equipment and kitchens
• White goods
• Gas tanks and gas cylinders
• Connecting of aluminium or copper coils in rolling mills
• Furniture
• Many other applications
Friction Stir Welding - Process advantages
The process advantages result from the fact that the FSW process (as all friction welding of metals) takes place in the solid phase below the melting point of the materials to be joined. The benefits therefore include the ability to join materials which are difficult to fusion weld, for example 2000 and 7000 aluminium alloys.
• Low distortion, even in long welds
• Excellent mechanical properties as proven by fatigue, tensile and bend tests
• No arc
• No fume
• No porosity
• No spatter
• Low shrinkage
• Can operate in all positions
• Energy efficient
• Non-consumable tool
• No filler wire
• Can weld aluminium and copper of >50mm thickness.
The limitations of the FSW process are being reduced by intensive research and development. However, the main limitations of the FSW process are at present:
• Workpieces must be rigidly clamped
• Keyhole at the end of each weld
• Cannot make joints which required metal deposition (e.g. fillet welds)
