Adjustable FSW Tool Assembly for High-Temperature Wear Resistance
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Solution Overview
Problem
Friction stir welding tools with integrally manufactured shoulders and probes made of hot tool steel suffer from low high-temperature wear resistance, limiting their use to low-melting-point materials and requiring frequent replacement, which is costly and inefficient for high-strength, high-melting-point materials like iron-and-steel alloys, stainless steel, or titanium alloys.
Innovation Solution
A friction stir welding tool with an adjustable probe length and shoulder groove depth, featuring a self-locking assembly structure and high-hardness materials like Co alloy, W-based cemented carbide, or PCBN, allowing for rapid adjustment and replacement of components to maintain optimal welding conditions and improve weld quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the shoulder and probe are integrally manufactured from hot tool steel, then the tool structure is simple and manufacturing cost is reduced, but high-temperature wear resistance is low and the tool must be frequently replaced
Solution Approach 1:
The tool is divided into separate components: the body (made of hot tool steel) and the insert (made of high-hardness material). The insert is detachably mounted on the body through a mounting hole, allowing the insert to be replaced independently when worn. This segmentation enables the use of inexpensive hot tool steel for the main body while using expensive high-hardness material only for the wear-prone insert portion.
Solution Approach 2:
Different parts of the tool have different material properties optimized for their specific functions. The body uses hot tool steel for thermal resistance and structural support, while the insert uses high-hardness material (such as ceramic or PCBN) specifically for the friction stir welding contact area where wear resistance is critical. This local optimization resolves the contradiction between overall manufacturing simplicity and localized wear resistance.
2Reliability
If high-hardness materials like PCBN are used for the probe and shoulder, then high-temperature wear resistance is improved, but material cost increases significantly
Solution Approach 1:
The tool is segmented into a reusable body and a replaceable insert. Only the insert (the small wear-prone portion) is made of expensive high-hardness material, while the majority of the tool body is made of inexpensive hot tool steel. This reduces the total amount of expensive material needed while maintaining wear resistance where it is most needed.
Solution Approach 2:
The insert is designed to be replaceable when worn, allowing the expensive high-hardness material to be recovered and reused in a new insert rather than discarding the entire tool. The reusable body retains its value and can accommodate multiple inserts over time, significantly reducing the effective cost per welding operation.
3Ease of repair
If the probe and shoulder are made as separate replaceable components, then component replacement becomes possible, but the assembly structure becomes more complex
Solution Approach 1:
The tool is segmented into a body and an insert that can be independently replaced. The insert is mounted through a simple mounting hole with a pressing-fit or interference-fit structure, creating a straightforward assembly that requires minimal fastening mechanisms while enabling easy replacement of the wear-prone insert.
Solution Approach 2:
The insert is extracted as a separate, removable component from the tool body. The mounting hole provides a simple interface that allows the insert to be taken out and replaced without complex disassembly procedures, balancing replaceability with structural simplicity.
4Ease of manufacture
If the probe length and shoulder groove depth are fixed, then the tool structure is simple, but welding quality cannot be optimized for different materials and conditions
Solution Approach 1:
The tool design transitions from fixed dimensions to adjustable dimensions. The insert can be selected or modified to provide different probe lengths and shoulder groove depths, allowing the tool to adapt to different welding conditions and material types while maintaining a simple overall structure through the reusable body.
Solution Approach 2:
The tool allows changes in critical parameters (probe length, shoulder groove depth) by replacing the insert with different specifications. This enables optimization of welding quality for different materials and conditions without redesigning the entire tool structure, achieving parameter flexibility through component interchangeability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables homogeneous friction stir welding, improves weld quality by allowing for real-time adjustment of probe length and shoulder depth, and facilitates economic replacement of worn parts, making high-quality welding feasible for high-strength materials without the need for costly tool replacement.
Implementation Method 1
the probe constituting the tool is brought into tight contact with a joint line therebetween, the tool is rotated until sufficient heat is generated, the temperature of the materials reaches a melting point by friction heat
Data Source
AI summary
Disclosed is a friction stir welding tool with an adjustable probe length and shoulder groove depth, wherein a support shaft, made of a material having low thermal conductivity so as to inhibit thermal conduction between a probe and a shank, is coupled to the center of an upper locking member together with the shank, the probe and inner and outer shoulders are coupled inside a lower part of the upper locking member, and a lower locking member is fastened and fixed to the lower part of the upper locking member, and a washer and a locking nut are fastened to an upper part of the lower locking member, whereby the locking nut pushes the lower locking member via the washer.