FSW Tool

Using our original manufacturing method, we have developed an Ir-based alloy tool that solves the problems of insufficient high temperature strength, insufficient toughness, and reactivity with the materials to be welded.
Its oxidation resistance is superior to that of other metals with high melting points, enabling welding of various materials.

Iridium Tool for FSW (Friction Stir Welding)

Friction stir welding (FSW) is a solid state welding method that uses the frictional heat generated between the workpiece materials and the tool, enabling plastic flow between the workplace materials due to the stirring action of the tool. It has the advantage of low strength deterioration of the joint and little deformation after welding, and for aluminum and its alloys, it has already been put into practical use in the automobile, railway, aerospace, etc. fields where reliability is required.
On the other hand, although research and development is advancing, FSW has not been put into practical use for steel materials, which account for the majority of metal production. One of the reasons for this is that tools for FSW of a material having a high melting point and high temperature strength, such as a steel material, have not yet been found. Therefore, we worked to develop a new alloy tool made from Iridium (Ir), which is Furuya Metal's specialty. Tools for FSW of steel materials are exposed to temperatures as high as 1000℃ to 1200℃. Oxidation loss and oxide formation of the tool during FSW can accelerate tool wear. Most metals with melting points above 2000℃ are heavily affected by oxygen in the temperature range of 1000℃ to 1200℃, whereas Iridium (Ir) is the most resistant to oxidation, with little loss or gain in weight.
We have also developed a tool that can increase the high-temperature strength and high-temperature hardness by alloying Ir, which allows it to weld high-temperature materials such as steel. With this Ir alloy tool, we have succeeded in FSW of steel materials, titanium, oxide dispersion strengthened platinum, and Mo, which has a melting point of more than 1000℃ higher than that of iron.

Full Body Type
Tip Type
Spiral Machining
FSW of stainless steel using an Ir alloy tool

Procedure for Executing FSW

Start (Insertion) Start (Insertion) End (Withdrawal)
  1. (1) Two materials to be welded are butted and restrained.
  2. (2) A tool rotating at high speed is inserted in the abutting surface, and the shoulder is brought into contact with the material.
    (The probe is inserted into the material.)
  3. (3) Frictional heat generated between the tool and the material softens the material, and the rotating tool moves in the welding direction.
  4. (4) The softened material is stirred and is continuously forced to the rear of the tool while flowing around the tool, and the two materials are welded.
  5. (5) When the welding is completed up to the designated position, the tool is withdrawn from the material.

Application Example

The Ir alloy tool can be applied to
high-temperature materials such as
stainless steel.

Heat Resistance

The tool does not soften even if
annealed at 1500℃ after plasticity

Oxidation Resistance

Oxidation resistance is superior to
other metals with high melting points.

FSW of 304 Stainless Steel Using Ir Alloy Tool

: 1330rpm-320mm/min
Stir-in-plate without shielding gas
Tool Material
: IA02Z
Tool Dimensions
: Probe diameter: 6mm. Probe height: 1.4mm.
Shoulder diameter: 15mm
Workpiece Material
: SUS304, 2mm thick
304 stainless steel after stir-in-plate FSW using an Ir alloy tool
The tool wears away, but can be re-machined because it does not break.
Tool Appearance after FSW