Inclined Weld Interface Thermal Matching in Rotary Friction Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In rotary friction welding, an inclined weld interface can lead to biased outflow of expelled material, causing rotation of the weld interface and compromising weld integrity due to uneven heat distribution and contamination issues.
Innovation Solution
The process involves aligning axisymmetric workpieces with inclined annular weld surfaces that are parallel to each other, featuring convexities with tapered side surfaces to ensure thermal matching and controlled heat flow, reducing bias in material expulsion and promoting a symmetrical heat-sink effect, thereby enhancing weld integrity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an inclined weld interface is used in rotary friction welding, then the welding process can join axisymmetric workpieces with non-perpendicular interfaces, but the expelled material flows biasedly causing rotation of the weld interface and compromising weld integrity
Solution Approach 1:
The patent applies asymmetry by providing convexities on only one of the two workpieces at the weld interface. This asymmetric configuration creates a specific heat flow pattern where the convexity acts as a localized heat source, generating a thermal gradient that drives symmetric outward flow of expelled material despite the inclined weld interface orientation. The asymmetric convexity design enables the system to achieve symmetric material expulsion behavior, preventing weld interface rotation and maintaining weld integrity while accommodating non-perpendicular interface angles.
2Adaptability or versatility
If an inclined weld interface is used, then non-perpendicular joining is enabled, but heat distribution becomes uneven leading to contamination issues
Solution Approach 1:
The asymmetric convexity configuration on one workpiece creates a controlled thermal field that compensates for the inclined interface geometry. The convexity generates localized heating that establishes a thermal gradient directed perpendicular to the weld interface, ensuring uniform heat distribution across the interface despite its inclination. This controlled thermal field promotes symmetric material flow and effective contaminant expulsion, preventing contamination while enabling non-perpendicular weld interface orientation.
3Manufacturing precision
If convexities with tapered side surfaces are used, then thermal matching and controlled heat flow are achieved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by providing convexities with specific tapered side surfaces only at the localized weld interface region of one workpiece, rather than modifying the entire workpiece geometry. The convexity features are concentrated precisely where thermal matching is needed, with tapered side surfaces angled between 30-60 degrees to control heat flow direction. This localized geometric modification achieves the desired thermal matching and heat flow control while minimizing overall device complexity, as only a small portion of the workpiece requires the complex convexity geometry.
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 allows for controlled heat distribution and reduced contamination, leading to a more predictable and efficient welding process with improved weld integrity by minimizing rotation and defects, and promoting rapid expulsion of interface contaminants.
Implementation Method 1
rotary friction welding is the process for welding together two bodies or workpieces by converting mechanical energy to heat energy by the friction between the engaging weld surfaces of the two workpieces
Implementation Method 2
material being expelled sideways from a plasticised zone at the interface as flash
Data Source
Figure 1
Figure 2(a)~2(e)
Figure 3(a)~3(d)
AI summary
A rotary friction welding process is provided. The process includes: providing a first axisymmetric workpiece (11) having a first annular weld surface (13), and a second axisymmetric workpiece (21) having a second annular weld surface (23), aligning the workpieces (11, 21) on a common axis with the weld surfaces facing each other, rotating one workpiece (11) about the axis relative to the other workpiece (21), and engaging the workpieces (11, 21) at the first and second weld surfaces (13, 23) such that the rotation raises the temperature at the weld surfaces (13, 23) to create a weld interface, and ceasing the rotation and allowing the weld interface to cool to weld the workpieces (11, 21) together at the interface. The first annular weld surface (13) is at a radially inward extent of the first workpiece (11), and the second annular weld surface (23) is at a radially outward extent of the second workpiece (21). On a longitudinal section through the aligned workpieces (11, 21), the first and second annular weld surfaces (13, 23) are inclined from the radial direction and are substantially parallel to each other such that the cooled weld interface is correspondingly inclined from the radial direction. On the longitudinal section through the aligned workpieces, each of the first and second annular weld surfaces (13, 3) is flanked by radially inner and outer side surfaces (14, 15 ; 24, 25) which are angled from their respective weld surface (13, 23), the first weld surface (13) and its side surfaces being shaped to thermally match the second weld surface (23) and its side surfaces (14, 15 ; 24, 25) across a line of initial contact of the first and second weld surfaces (13, 23) such the heat flows from the weld at all the side surfaces (14, 15 ; 24, 25) are substantially equal.