Segmented Tungsten Die Assembly for High-Temperature Friction Stir Processing
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Solution Overview
Problem
Conventional friction stir processing tooling is inadequate for processing high-temperature metals and large diameter workpieces, as it fails to withstand the extreme temperatures and forces involved, leading to deformation and wear issues.
Innovation Solution
A friction stir processing system utilizing a rotatable die assembly with multiple die segments made of tungsten, coupled with a mandrel assembly that includes a cooling channel and heat exchanger, allowing for efficient processing of high-temperature metals like titanium and Inconel, and enabling the processing of larger diameter workpieces by distributing temperature and wear loads across multiple segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional friction stir processing tooling is used, then the processing of high-temperature metals and large diameter workpieces is attempted, but the tooling experiences deformation and wear due to inability to withstand extreme temperatures and forces
Solution Approach 1:
The die assembly is divided into multiple die segments that are coupled together to form a complete die surface. Each segment can be independently replaced if worn, and the segments collectively distribute the thermal and mechanical loads, preventing the deformation issues experienced with conventional single-piece tooling when processing high-temperature metals
Solution Approach 2:
The die segments are formed from tungsten, a material with superior high-temperature strength and resistance to thermal deformation. This composite material approach (using tungsten die segments coupled to a steel die body) allows the tooling to withstand the extreme temperatures and forces involved in processing high-temperature metals without deformation
2Reliability
If conventional single-piece die tooling is used, then the die surface must withstand all temperature and wear loads, but this leads to rapid wear and deformation
Solution Approach 1:
The die surface is segmented into multiple replaceable segments that distribute the wear load. Each segment experiences reduced individual wear stress compared to a single-piece die, and worn segments can be replaced without replacing the entire die assembly, significantly improving overall die surface durability
Solution Approach 2:
The die segments are formed from tungsten, a material with superior wear resistance and high-temperature strength. This local application of high-performance material at the die surface (where wear and temperature are most severe) while using standard steel for the die body provides targeted durability improvement where it is most needed
3Reliability
If multiple die segments are used, then temperature and wear loads are distributed across segments improving durability, but the device complexity increases
Solution Approach 1:
The die assembly is segmented into multiple die segments coupled to the die stem, allowing for improved processing capability and durability. The segments are designed to be relatively simple individual components that can be manufactured and replaced independently, managing the complexity through modularity
Solution Approach 2:
The die segments serve multiple functions: they form the die surface for shaping, distribute thermal loads, distribute wear loads, and can be independently replaced for maintenance. This multi-functionality of the segmented design improves processing capability while the modular nature helps manage device complexity
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
The system effectively processes high-temperature metals and large diameter workpieces with improved durability and efficiency, reducing deformation and wear, and producing materials with superior metallurgical properties such as fine grain microstructure, higher strength, and enhanced corrosion resistance.
Implementation Method 1
an outer mandrel disposed around the inner mandrel, wherein the inner mandrel and the outer mandrel define a container volume
Implementation Method 2
rotating a die surface of a die assembly against a billet, wherein the die assembly comprises a plurality of die segments coupled to a die stem
Data Source
AI summary
A friction stir processing system can include a rotatable die assembly. The rotatable die assembly can include a die body and a plurality of die segments. The die body includes a die base and a die stem. The die stem extends axially from the die base, the die stem defines an extrusion cavity, and the die body is formed from a first material. The plurality of die stems are coupled to the die stem. The plurality of die segments are disposed around the extrusion cavity to collectively form a die surface opposite to the die base. The plurality of die segments are formed from a different material than the die body.