Introduction
Friction Stir Welding (FSW) was invented by Wayne
Thomas at TWI (The Welding Institute), and the first
patent applications were filed in the UK in December
1991
Thomas at TWI (The Welding Institute), and the first
patent applications were filed in the UK in December
1991
Friction Stir Welding is a solid-state process, which
means that the objects are joined without reaching
melting point. This opens up whole new areas in
welding technology. Using FSW, rapid and high
quality welds of 2xxx and 7xxx series alloys,
traditionally considered unweldable, are now
possible.
means that the objects are joined without reaching
melting point. This opens up whole new areas in
welding technology. Using FSW, rapid and high
quality welds of 2xxx and 7xxx series alloys,
traditionally considered unweldable, are now
possible.
Working
In FSW, a cylindrical shouldered tool with a profiledpin is rotated and plunged into the joint area
between two pieces of sheet or plate material. The
parts have to be securely clamped to prevent the
joint faces from being forced apart. Frictional heat
between the wear resistant welding tool and the
workpieces causes the latter to soften without
reaching melting point, allowing the tool to traverse
along the weld line. The plasticised material,
transferred to the trailing edge of the tool pin, is
forged through intimate contact with the tool
shoulder and pin profile. On cooling, a solid phase
bond is created between the workpieces.
Weldable materials
A number of high melting temperature alloys have been
successfully joined using FSW. Many other applications are
still to be explored. Alloys already successfully joined using
FSW include:
1. Carbon steels, including high strength steels, pipe steels,
and Dual-Phased/TRIP steels
2. Stainless steels, including Super Duplex, Super Chrome
and Ferritic. These alloys exhibit a refined grain structure
in the weld zone. Friction Stir Welding of these alloys
offers numerous benefits, such as
• Critical Pitting Temperature (CPT) is 20ยบ C higher
than arc-welding processes
• FSW does not introduce harmful intermetallics
• FSW retains the proper ratio of austenite and ferrite
• FSW does not form excessive amounts of martensite
• FSW creates a matching fusion zone without
reinforcement
3. Ni-based alloys
4. Other non-weldable alloys.
A number of high melting temperature alloys have been
successfully joined using FSW. Many other applications are
still to be explored. Alloys already successfully joined using
FSW include:
1. Carbon steels, including high strength steels, pipe steels,
and Dual-Phased/TRIP steels
2. Stainless steels, including Super Duplex, Super Chrome
and Ferritic. These alloys exhibit a refined grain structure
in the weld zone. Friction Stir Welding of these alloys
offers numerous benefits, such as
• Critical Pitting Temperature (CPT) is 20ยบ C higher
than arc-welding processes
• FSW does not introduce harmful intermetallics
• FSW retains the proper ratio of austenite and ferrite
• FSW does not form excessive amounts of martensite
• FSW creates a matching fusion zone without
reinforcement
3. Ni-based alloys
4. Other non-weldable alloys.
Automotive applications
In principle, all aluminium components in a car can be friction stir welded: bumper beams, rear spoilers, crash boxes, alloy wheels, air suspension systems, rear axles, drive shafts, intake manifolds,stiffening frames, water coolers, engine blocks, cylinder heads,dashboards, roll-over beams, pistons, etc.
In principle, all aluminium components in a car can be friction stir welded: bumper beams, rear spoilers, crash boxes, alloy wheels, air suspension systems, rear axles, drive shafts, intake manifolds,stiffening frames, water coolers, engine blocks, cylinder heads,dashboards, roll-over beams, pistons, etc.
TOOLS
No comments:
Post a Comment