Dissimilar Metal Joining via Intermediary Layer Welding

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Solution Overview

Problem

Joining dissimilar metals is challenging due to galvanic corrosion, which is exacerbated by the use of electrically insulating layers that also hinder radio-frequency signal reception and complicate manufacturing processes.

Innovation Solution

A method involving a laminate structure with a third metal layer chemically similar to either the first or second metal layer, which is welded through a clearance opening in a dissimilar metal layer, reducing galvanic corrosion and simplifying weld schedules by maintaining constant contact between dissimilar metal layers via roll bonding and spot welding or magnetic pulse welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrically insulating layer of polymer adhesive is disposed between dissimilar metals to prevent galvanic corrosion, then corrosion resistance is improved, but radio-frequency signal reception deteriorates and device complexity increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidradio-frequency signal reception

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A third metal layer is introduced as an intermediary between the first and second dissimilar metal layers. This intermediate metal layer enables direct metal-to-metal contact for electrical continuity and RF signal reception while preventing galvanic corrosion through proper material selection and layer configuration, eliminating the need for polymer adhesive layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If an electrically insulating layer of polymer adhesive is used between dissimilar metals, then galvanic corrosion is prevented, but manufacturing complexity increases due to wide variety of weld schedules

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidweld schedules

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The third metal layer is selected to be chemically similar to at least one of the dissimilar metal layers it contacts. This chemical similarity enables the use of uniform welding parameters and simplified weld schedules throughout the assembly process, as the intermediate layer can be welded to both adjacent layers using compatible procedures, reducing the variety of weld schedules required.

Inventive Principle:

Principle #33Homogeneity

3Ease of manufacture

If dissimilar metals are joined directly without intermediate layers, then manufacturing simplicity is improved, but galvanic corrosion accelerates

Engineering Contradiction:

Improvejoining process simplicityVSAvoidcorrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A third metal layer serves as a mediating element between the two dissimilar metal layers. This intermediate layer maintains direct metal-to-metal contact for structural integrity and electrical continuity while protecting against galvanic corrosion through proper material selection, achieving both manufacturing simplicity and corrosion resistance.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If dissimilar metals are joined with polymer adhesive to prevent corrosion, then corrosion resistance is improved, but production speed deteriorates due to complex weld schedules

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmanufacturing speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

By changing the material parameters of the intermediate layer to be chemically similar to at least one adjacent layer, the welding parameters can be standardized and simplified. This reduces the variety of weld schedules required, enabling faster production cycles while maintaining corrosion protection.

Inventive Principle:

Principle #35Parameter changes

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 galvanic corrosion, improves radio-frequency signal reception, and simplifies manufacturing by eliminating the need for diverse weld schedules, while maintaining the benefits of using dissimilar metals in automotive and other applications.

Implementation Method 1

at least two metal layers that are chemically similar are welded together through a clearance opening located in a metal layer that is not chemically similar to the at least two metal layers

Methodology Applied

Scientific EffectWelding: Welding

Implementation Method 2

roll bonding a first metal layer to a second metal layer to form a first laminate

Methodology Applied

Scientific EffectRoll bonding:

Implementation Method 3

frictional contact between a hemmed portion of the first metal layer, the second metal layer and the third metal layer keeps the first metal layer, the second metal layer and the third metal layer in contact with each other

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10611125B2Method for joining dissimilar metals and articles comprising the same

Publication Date: 2020.04.07 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Disclosed herein is an article comprising a first metal layer; a second metal layer that is chemically different from the first metal layer; and a third metal layer disposed between the first metal layer and the second metal layer and contacting both the first metal layer and the second metal layer; where the third metal layer is chemically similar to either the first metal layer or the second metal layer; where at least two metal layers that are chemically similar are welded together through a clearance opening located in a metal layer that is not chemically similar to the at least two metal layers.