Automobile Structural Laminate Bonding to Prevent Galvanic Corrosion
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Solution Overview
Problem
Existing methods for manufacturing automobile structural materials face challenges in achieving high joining strength, suppressing electrolytic corrosion, and optimizing the joining process time and open time for multi-material assemblies.
Innovation Solution
A method involving a pre-joining process to form a layered body with a first metal member, a solid joining agent containing an amorphous thermoplastic resin, and a second metal member, followed by a joining process where the layered body is heated and pressurized to melt the joining agent, effectively joining the metal members with high strength and preventing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If arc welding is performed by FCW with steel plates layered on an aluminum-alloy hollow profile, then joining strength is improved, but electrolytic corrosion occurs between dissimilar metals and the process complexity increases
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the aluminum-alloy hollow profile and steel plates. This resin layer prevents direct contact between dissimilar metals, thereby eliminating electrolytic corrosion while still enabling effective joining through the resin's adhesive properties and thermal bonding capability.
Solution Approach 2:
The conventional arc welding process (FCW) is replaced with a thermal pressing process using a resin layer. Instead of using electrical arcs to melt and fuse metals, the invention uses heat and pressure to melt the resin, which then bonds the metal components together, avoiding the electrolytic corrosion issues associated with direct metal-to-metal welding.
2Strength
If multi-material assemblies are joined using conventional methods, then joining strength is achieved, but the joining process time is long and open time is short
Solution Approach 1:
The invention optimizes the resin layer's physical and chemical parameters, including its glass transition temperature, melting point, and viscosity characteristics. By carefully selecting resin components and adjusting their ratios, the process achieves rapid bonding at moderate temperatures and pressures, significantly reducing both joining process time and required open time compared to conventional multi-step joining methods.
3Adaptability or versatility
If different metal members with different Young's moduli are joined, then structural performance is improved, but achieving high joining strength while suppressing corrosion becomes more difficult
Solution Approach 1:
The resin layer serves as a protective intermediary that prevents direct galvanic contact between dissimilar metals with different Young's moduli. This allows the structural benefits of multi-material assemblies to be realized while the resin barrier eliminates the reliability issues caused by electrolytic corrosion between incompatible metals.
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 enables the manufacture of automobile structural materials with high joining strength, reduced electrolytic corrosion, and efficient processing, achieving a short joining process time and a long open time.
Implementation Method 1
a joining process of heating and pressurizing the layered body, melting the solid joining agent, thereby joining the first metal member and the second metal member
Implementation Method 2
different kinds of metal members to be joined to each other with high joining strength, suppressing electrolytic corrosion between the metal members
Data Source
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AI summary
This method for manufacturing an automobile structural material according to an embodiment comprises: a pre-bonding step for preparing a laminate in which a first metal member, a solid bonding agent having, as a main component, an amorphous thermoplastic resin that is at least one among a thermoplastic epoxy resin and a phenoxy resin, and a second metal member are arranged in this order; and a bonding step for melting the solid bonding agent by heating and pressing the laminate, and bonding the first metal member and the second metal member, wherein the Young's modulus of the second metal member is at least 5 GPa higher than that of the first metal member.