Friction Welding with Spike Forge Upset for Dissimilar Alloys
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Solution Overview
Problem
Existing friction welding methods for dissimilar alloys, such as Ti-6-4 and Ti-17, are prone to defects due to insufficient displacement rate and compressive force during the forge phase, particularly when oscillator movement is discontinued.
Innovation Solution
A friction welding method involving rapid oscillation decay coupled with a spike in axial force to enhance material upset, utilizing a spike forge upset mechanism that rapidly increases axial force near the end of the weld cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If machine controls are tuned to prevent weld from under or overshooting desired set points, then uniform upset rate and predictable total upset are achieved, but rate of application and amount of forge axial force are restricted
Solution Approach 1:
The patent applies periodic reciprocating motion during the friction welding process to generate friction heat and promote material flow. The oscillating motion is discontinued during the forge phase, creating periodic cycles of heating and forging that enable defect-free welds of dissimilar alloys while maintaining controlled upset rates.
Solution Approach 2:
The patent changes key process parameters during welding, specifically increasing the rate of application and amount of forge axial force beyond conventional limits by adjusting machine control settings. This allows sufficient compressive force to be applied when oscillator movement is discontinued, preventing defects in dissimilar alloy combinations.
2Manufacturing precision
If horizontal displacement rate and compressive forces are reduced to prevent overshooting, then weld precision is improved, but weld quality for dissimilar alloys deteriorates due to insufficient displacement rate and compressive force
Solution Approach 1:
The patent applies preliminary friction heating through reciprocating motion before the forge phase to generate sufficient heat and soften the material interface. This preliminary thermal preparation enables subsequent high-rate material flow and defect-free welding when compressive forces are applied, even for dissimilar alloys with different thermal properties.
Solution Approach 2:
The patent employs dynamic control of the welding process, transitioning from oscillating motion during heating to static compression during forging. The system dynamically adjusts between these states, allowing high compressive forces to be applied only when needed during the forge phase, thereby achieving both precision and quality for dissimilar alloys.
3Productivity
If oscillator movement is discontinued during forge phase, then welding process progresses, but material upset is insufficient leading to defects in dissimilar alloys
Solution Approach 1:
The patent uses mechanical vibration in the form of reciprocating oscillator motion during the conditioning and burn-off phases to generate friction heat and prepare the material interface. This vibrational heating enables subsequent material upset during the forge phase when oscillation is discontinued, ensuring adequate material flow for defect-free welds.
Solution Approach 2:
The patent maintains continuous useful action by transitioning smoothly from oscillating friction heating to static compressive forging. The heat generated during oscillation continues to soften the material, and the compressive force is continuously applied during the forge phase, ensuring uninterrupted material flow and upset even when oscillator movement is discontinued.
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
This approach produces defect-free bi-alloy welds, enabling the use of materials optimized for performance and weight by enhancing material flow and weld quality.
Implementation Method 1
The components to be bonded together are linearly or translationally rubbed one against the other with a reciprocating translational motion so that at their interface sufficient heat is generated by friction to effect the weld
Data Source
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AI summary
A friction welding method includes: applying axial force to first and second metallic components (14, 16) so as to force the components (14, 16) against each other at an interface therebetween, while oscillating the two components (14, 16) relative to each other in a cyclic motion, so as to generate friction and heat at the interface; rapidly stopping the cyclic motion; and applying a spike in the axial force to complete a weld between the first and second components (14, 16).