Dissimilar Metal Butt Joining With a V-Gap Friction Stir Interface
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Solution Overview
Problem
Conventional joining methods for metallic members of different materials face complexity in forming inclined faces and achieving surface contact, requiring precise angle matching and increasing the risk of joining defects due to uneven softening temperatures.
Innovation Solution
A joining method using a rotary tool with a tapered stirring pin, where one metal member has a vertical face and the other an inclined face, forming a V-shaped gap for easy butting and reducing heat input by only contacting the first metal member, allowing for friction stir welding while controlling the plasticized region to prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both metal members are given inclined faces to achieve surface contact, then joining is possible, but the preparation process and butting process become complicated
Solution Approach 1:
The invention applies asymmetry by giving only one metal member (the second one) an inclined face, while the first metal member maintains a vertical face. This asymmetric configuration enables surface contact and reliable joining without requiring both members to have complex inclined faces, thereby reducing overall process complexity while maintaining joining reliability.
Solution Approach 2:
Instead of the conventional approach where both members have inclined faces meeting at equal angles, the invention inverts the approach by having one vertical face and one inclined face. This inversion simplifies the butting process while still achieving the necessary surface contact for reliable joining.
2Reliability
If both metal members are given inclined faces with equal angles, then surface contact occurs, but the preparation process becomes complicated
Solution Approach 1:
The invention uses asymmetry by configuring one metal member with a vertical face and the other with an inclined face, eliminating the need for precise angle matching between both members. This significantly eases the preparation process while ensuring reliable surface contact for joining.
3Reliability
If heat input is increased to join metal members with different melting points, then joining is achieved, but excessive burrs are generated due to softening
Solution Approach 1:
The invention applies local quality by directing heat input selectively to specific regions. The inclined face configuration and controlled joining process localize heat application to where it is most needed, preventing excessive heat accumulation that would cause softening and burr generation in the first metal member, while still achieving sufficient joining strength.
Solution Approach 2:
The invention utilizes parameter changes by controlling the joining conditions (temperature, pressure, speed) to match the different melting points of the two metal members. By adjusting these parameters and using the inclined face geometry, the process achieves reliable joining without generating excessive heat that would cause softening and burr formation.
4Reliability
If heat input is increased to join metal members of different materials, then joining is achieved, but joining defects occur due to uneven softening
Solution Approach 1:
The inclined face configuration creates local quality variations in heat distribution and material flow during joining. This localized approach ensures uniform softening in the critical joining zone while preventing uneven softening that would lead to defects, thereby maintaining high joining precision and strength.
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 easy joining of metallic members with different materials by reducing the complexity of forming inclined faces and minimizing heat input, thereby preventing excessive burrs and joining defects, while ensuring strong interdiffusion across the interface.
Implementation Method 1
a joining process configured to join the first metal member and the second metal member together by inserting the rotating rotary tool from only a front face of the first metal member and relatively moving the rotary tool along the butted portion while only the stirring pin is in contact with at least the first metal member
Implementation Method 2
a joining process configured to join the first metal member and the second metal member together by inserting the rotating rotary tool from only a front face of the first metal member and relatively moving the rotary tool along the butted portion while only the stirring pin is in contact with at least the first metal member
Implementation Method 3
ensuring strong interdiffusion across the interface
Data Source
AI summary
The present invention includes: a preparation process configured to provide a first metal member including an end portion with a vertical face, and a second metal member including an end portion with an inclined face, a higher melting point and a smaller plate thickness than the first metal member; a butting process configured to butt the end portions of the first metal member and the second metal member against each other and form a butted portion with a V-shaped gap; and a joining process configured to join the first metal member and the second metal member together by inserting the rotating rotary tool from only a front face of the first metal member and relatively moving the rotary tool along the butted portion while only the stirring pin is in contact with at least the first metal member.