Aircraft Aluminum Alloy Frame Forming in T8 Temper

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Solution Overview

Problem

The manufacturing of aircraft components from aluminum-lithium alloys is hindered by the poor ductility and small work hardening coefficient of the T8 state, leading to increased costs due to mechanical machining or extrusion molding, and existing methods for 7000-series alloys are not applicable to aluminum-lithium alloys.

Innovation Solution

A method involving solution heat treatment followed by multi-stage roll forming to impart compressive strain, allowing the aluminum-lithium alloy to achieve the T8 state, thereby reducing manufacturing costs by combining forming and strain imparting processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical machining is used to manufacture formed components from aluminum-lithium alloy, then the component shape can be achieved, but material yield decreases and manufacturing cost increases

Engineering Contradiction:
Improvecomponent shape accuracyVSAvoidmaterial yield
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies parameter changes by controlling the temper state of aluminum-lithium alloy to T8 state with specific strength and ductility parameters, enabling direct roll forming without machining. The alloy composition parameters (Al-Li-Cu-Mg system) are optimized to achieve both formability and final strength requirements, eliminating material waste from machining operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical machining system with a roll forming system that directly shapes the aluminum-lithium alloy sheets. By substituting subtractive machining with additive/forming processes, material yield is significantly improved while achieving the required component geometry through controlled plastic deformation.

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

2Manufacturing precision

If extrusion molding is used to manufacture formed components from aluminum-lithium alloy, then component shape can be achieved, but material cost increases

Engineering Contradiction:
Improvecomponent shape accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent optimizes the alloy temper parameters to T8 state and controls the roll forming process parameters (roller configuration, passing speed, temperature) to achieve complex component shapes directly from sheets, providing a more cost-effective alternative to extrusion molding while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

3Strength

If aluminum-lithium alloy in T8 state is used, then strength is improved, but ductility decreases and work hardening coefficient becomes small

Engineering Contradiction:
Improvealloy strengthVSAvoidformability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing roll forming operations while the aluminum-lithium alloy is in a softened state (before final T8 tempering). The forming is done on pre-heated or annealed material that has not yet undergone the full age-hardening process, allowing easy deformation. The T8 tempering is then applied after forming to achieve the required strength, thus decoupling the formability requirement from the strength requirement.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If existing manufacturing methods for 7000-series alloys are applied to aluminum-lithium alloys, then process experience can be utilized, but the temper cannot be adjusted to T8 state

Engineering Contradiction:
Improveprocess applicabilityVSAvoidtemper control accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent adapts the manufacturing process by changing the temper control parameters specifically for aluminum-lithium alloys. While maintaining the general roll forming methodology from 7000-series alloy processing, the patent modifies the heat treatment parameters (solution treatment temperature, aging temperature and time) to achieve the T8 state specific to Al-Li alloys, which have different hardening characteristics compared to 7000-series alloys.

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 method enables the cost-effective production of aircraft components with improved strength and corrosion resistance by achieving the T8 state in aluminum-lithium alloys, reducing material yield loss and production costs.

Implementation Method 1

subjecting the material made of an aluminum alloy to the solution heat treatment

Methodology Applied
Scientific EffectSolution heat treatment: Heat Treatment

Implementation Method 2

subjecting the material to artificial age-hardening treatment

Methodology Applied
Scientific EffectArtificial age-hardening treatment: Heat Treatment

Data Source

PatentEP2937435B1Method of manufacturing a frame made of aluminum alloy for aircraft use
Publication Date: 2024.06.12 KAWASAKI JUKOGYO KK
  • EP2937435B1 patent drawingFigure 1
  • EP2937435B1 patent drawingFigure 2
  • EP2937435B1 patent drawingFigure 3

AI summary

A method of manufacturing a formed component for aircraft use according to the present invention includes: subjecting a material made of an aluminum alloy to solution heat treatment; then forming the material into a predetermined shape under cold working conditions; and thereafter subjecting the material to artificial age-hardening treatment. Under the cold working, the material is formed into the predetermined shape while a strain corresponding to a temper T8 is being imparted to the material by a roll forming apparatus. This makes it possible to manufacture a formed component for aircraft use made of an aluminum alloy in a T8 state at a lower cost than conventional art.