Method and system for joining metal workpieces to provide a workpiece assembly
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Solution Overview
Problem
Existing methods for fusing metal workpieces in confined spaces are inadequate, leading to issues such as heat-affected zones and material weakness.
Innovation Solution
A method involving an intermediate element with a ring element, rotated about its axis while heating elements heat the workpiece ends to a predetermined temperature, causing plastic deformation and recrystallization, resulting in a uniform, fine-grained microstructure without heat-affected zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fusion methods are used to join metal workpieces, then the workpieces can be connected, but heat-affected zones and material weakness are created
Solution Approach 1:
The heating process is segmented into discrete heating zones along the workpiece, with heating elements positioned at specific locations to create controlled thermal gradients. This segmentation allows different portions of the workpiece to be at different temperatures, enabling localized plastic deformation without overheating the entire assembly, thus avoiding extensive heat-affected zones.
Solution Approach 2:
The intermediate element is rotated dynamically during the joining process while maintaining axial engagement with the workpieces. This dynamic rotation creates continuous plastic deformation and shear stresses in the heated portions, promoting recrystallization and uniform fine-grained microstructure formation. The combination of dynamic rotation and controlled heating eliminates static heat-affected zones characteristic of conventional fusion methods.
2Manufacturing precision
If heating elements are used to reach predetermined temperature, then plastic deformation and recrystallization occur, but energy consumption increases
Solution Approach 1:
Heating elements are positioned to apply heat locally only to specific portions of the intermediate element and workpieces that require plastic deformation. The heating is not applied uniformly throughout the entire assembly but is concentrated in zones where thermal processing is needed, reducing overall energy consumption while achieving the desired microstructure in critical areas.
Solution Approach 2:
The intermediate element rotates continuously during heating and engagement, ensuring that the plastic deformation and recrystallization processes occur continuously rather than in discrete steps. This continuous action maximizes the effectiveness of the heating energy by constantly working the heated material, improving microstructure uniformity while minimizing total energy requirements compared to intermittent or prolonged heating cycles.
3Reliability
If the intermediate element is rotated during engagement, then uniform fine-grained microstructure is achieved, but device complexity increases
Solution Approach 1:
The rotation function and engagement function are merged into a single integrated process. The intermediate element serves both as the heating medium and as the rotating component that engages with the workpieces. This merging eliminates the need for separate rotation mechanisms and engagement devices, reducing overall system complexity while achieving uniform fine-grained microstructure through the combined action of heating and rotating during a single operation.
Solution Approach 2:
The intermediate element performs multiple functions simultaneously: it is heated by the heating elements, it rotates to create plastic deformation, and it engages with the workpieces to transfer the deformed material. This self-service approach where a single component performs heating, rotation, and engagement functions reduces the number of separate devices needed, simplifying the overall system while maintaining reliable microstructure uniformity.
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 method achieves a uniformly strong workpiece assembly with no heat-affected zones, using minimal energy for rotation and engagement, suitable for joining different metals in limited spaces.
Implementation Method 1
With heating elements positioned between the intermediate element and the first and second ends of the first and second workpieces, portions of the intermediate element and the first and second workpieces are heated to a predetermined hot working temperature
Implementation Method 2
The rotation of the intermediate element while the first and second ends are engaged with it result in at least part of the heated portions being subjected to plastic deformation, so that the material in the heated portions is subjected to shear stresses. This causes recrystallization of the material
Data Source
AI summary
A method and a system of forming a workpiece assembly including an intermediate element between first and second workpieces. A ring element is included in or on the intermediate element. The ring element is for rotating the intermediate element about the intermediate elements axis. With heating elements positioned between the intermediate element and the first and second ends of the first and second workpieces, portions of the intermediate element and the first and second workpieces are heated to a predetermined hot working temperature, in an inert (non-oxidizing) atmosphere. While the heated portions are at the predetermined hot working temperature, and while the intermediate element is rotated about its axis, one or both of the first and second workpieces are moved axially, to engage the first and second ends with the intermediate element.