Dissimilar-Material Junction Structure Using Through-Hole Arc Welding
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Solution Overview
Problem
Conventional methods for joining different materials, such as spot welding and riveting, are time-consuming, costly, and limit design freedom due to the need for complex shapes and resistance welding processes, which can result in insufficient nugget formation and reduced stiffness at required positions.
Innovation Solution
A junction structure using arc or plasma welding with a molten welding wire bonded through a through part in one material to another, allowing for easy joining of dissimilar materials with increased stiffness and design freedom by depositing the welding wire into and around a through part on the surface of the second material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spot welding is used to join different materials, then joining strength is achieved, but production time increases due to pressurization, energization, cooling, and transfer steps
Solution Approach 1:
The invention extracts the time-consuming pressurization and cooling steps from the welding process by using friction stir welding instead of spot welding. The friction stir welding process continuously stirs and welds the materials without requiring intermittent pressurization and cooling cycles, thereby reducing production time while maintaining joining strength.
Solution Approach 2:
The invention applies preliminary action by pre-positioning the rivet and configuring the through-part structure before welding. The rivet is inserted through the through-part, and the friction stir welding process then automatically performs the joining operation without requiring additional pressurization steps, thereby eliminating time loss associated with sequential operations.
2Strength
If rivets with complicated shapes are used to accommodate deformed material, then junction strength is maintained, but manufacturing cost increases due to high precision processing
Solution Approach 1:
The invention segments the rivet structure into a simple cylindrical body with a head, eliminating the need for complicated shapes like radius-chamfered parts or annular grooves. The through-part in the second material accommodates the rivet in its simple cylindrical form, thereby reducing manufacturing cost while maintaining junction strength through proper material deformation control.
Solution Approach 2:
The invention changes the material parameters and welding parameters to allow simple rivet shapes to achieve the required junction strength. By optimizing the friction stir welding parameters and material selection, the patent enables strong joints without requiring complex rivet geometries that would increase manufacturing cost.
3Strength
If adjacent rivets are placed close to each other to improve junction stiffness, then design flexibility increases, but nugget formation becomes insufficient due to current diversion
Solution Approach 1:
The invention replaces the electrical resistance welding system with a mechanical friction stir welding system. This substitution eliminates the current diversion problem that occurs when rivets are placed close together, as friction stir welding uses mechanical friction and stirring rather than electrical current to create the weld. Consequently, nugget formation remains reliable even with closely spaced rivets, improving both junction stiffness and reliability.
4Adaptability or versatility
If one side welding is required, then design freedom increases, but spot welding becomes unsuitable due to sandwich structure requirement
Solution Approach 1:
The invention inverts the welding approach by using friction stir welding from a single side instead of requiring sandwich structure spot welding from both sides. The friction stir welding tool accesses only one side of the joint, eliminating the need for sandwich structure and upper/lower electrodes, thereby enabling one side welding applications and significantly increasing design freedom.
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 significantly reduces production cycle time, increases stiffness at required positions, and enhances design freedom by simplifying the joining process and eliminating the need for complex fabrication, while maintaining high reliability in material bonding.
Implementation Method 1
a molten welding wire bonded to the first metallic material by arc welding through the through part along the thickness of the first metallic material
Implementation Method 2
the molten welding wire being deposited into the through part of the different material, the molten welding wire being deposited onto a region which is on the upper surface of the different material and surrounds the through part
Data Source
AI summary
A junction structure includes a first metallic material, a second material different in type from the first metallic material, and a welding wire as a third material similar to the first metallic material. The second material is stacked on the first material. The molten metal of the third metallic material is deposited by arc welding into the through part of the second material so as to form a flanged or tapered bead, so that the first and third metallic materials and the second material are fixed together.