Metal Component Bonding With Pulsed Current for Gap-Free Welds

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Solution Overview

Problem

Existing methods for bonding metallic components, such as forge welding, face challenges with physical gaps and contamination leading to weaker welds, despite surface cleaning and fluxing, as they fail to effectively eliminate reaction with the environment and ensure strong structural integrity.

Innovation Solution

A method that protects bonding surfaces from environmental reactions by plating, coating, or shielding with noble gases, and applies simultaneous force and electric current to induce joule heating and electroplasticity, allowing for improved bonding by pushing out contaminated metal and reducing gaps, while using lower welding temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface cleaning and fluxing are used to reduce oxidation, then bonding quality improves, but physical gaps and contaminated metal still remain in the joints

Engineering Contradiction:
Improvebonding qualityVSAvoidphysical gaps and contaminated metal
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies pulsed electric current to induce electroplasticity, which changes the physical state and flow characteristics of metal at the bonding interface. This enables the metal to flow and eliminate gaps and contaminants that conventional cleaning methods cannot remove, thereby resolving the contradiction between improved bonding quality and remaining harmful factors.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses pulsed electric current rather than continuous current, applying periodic action to induce electroplasticity in cycles. This periodic stimulation allows repeated cycles of metal softening, flow, and consolidation, effectively pushing out contaminants and closing gaps while maintaining bonding quality.

Inventive Principle:
Principle #19Periodic action

2Strength

If higher welding temperature is used to improve bonding, then metal flow and bonding strength improve, but energy consumption increases and material properties may deteriorate

Engineering Contradiction:
Improvebonding strengthVSAvoidwelding temperature
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical state of metal through electroplasticity induced by pulsed electric current, allowing effective bonding at lower temperatures. This parameter change enables metal flow and bonding without requiring high thermal energy, thus resolving the contradiction between bonding strength and energy consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces thermal heating with electroplasticity-induced metal flow. Instead of relying solely on thermal energy to soften and flow metal for bonding, the invention uses electric current to directly induce plastic deformation and metal flow, substituting mechanical/electrical action for thermal action and reducing energy requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional forge welding is used without electroplasticity, then process simplicity is maintained, but gaps and contaminants cannot be effectively eliminated

Engineering Contradiction:
Improveprocess simplicityVSAvoidjoint integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces pulsed electric current as a relatively simple periodic action to conventional forge welding. This addition induces electroplasticity that effectively eliminates gaps and contaminants without requiring complex equipment modifications, thus resolving the contradiction between process simplicity and joint integrity.

Inventive Principle:
Principle #19Periodic action

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 method enhances bonding quality by eliminating gaps and contaminants, achieving stronger welds with reduced temperature and stress, and eliminating the need for re-heat treatment, thus improving structural validity and mechanical properties.

Implementation Method 1

an electric current is passed through the bonding surfaces to joule heat and weld the bonding surfaces together

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The electric current may be pulsed to induce electroplasticity in the components to improve bonding across the joint

Methodology Applied
Scientific EffectElectroplasticity:

Data Source

PatentEP4201573A1Method of bonding metallic components to form machining preform
Publication Date: 2023.06.28 SPIRIT AEROSYSTEMS INC
  • EP4201573A1 patent drawingFigure 1
  • EP4201573A1 patent drawingFigure 2~6
  • EP4201573A1 patent drawing

AI summary

A method of bonding two or more metallic components into a single piece. The bonding surfaces of the metallic components are protected from reaction with the environment. A force is applied to the metallic components to push the bonding surfaces together. Simultaneous with applying the force, an electric current is passed through the bonding surfaces to joule heat and weld the bonding surfaces together to form the single piece. The bonding surfaces may be protected by plating with a noble metal, applying a coating, shielding with a noble gas, or placing into a vacuum. A press may be used to apply the force. The force and the electric current may be sufficient to push out metal around the joint of the bonding surfaces, and at least one of the bonding surfaces may be drafted to facilitate pushing out the metal. The electric current may be pulsed to induce electroplasticity.