Aluminum Alloy Sheet Processing for Isotropic Deep Drawability

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Solution Overview

Problem

Conventional methods for producing aluminum alloy sheets result in anisotropic properties due to high final cold reduction, leading to issues such as roping and earing, which compromise formability and production efficiency.

Innovation Solution

A method involving low final cold reduction and optional inter-annealing steps to achieve a balanced distribution of alpha and beta fibers, resulting in an isotropic microstructure with improved formability and drawability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high final cold reduction is applied to produce recrystallized grain structure, then strength is improved, but formability deteriorates due to anisotropic properties

Engineering Contradiction:
ImprovestrengthVSAvoidformability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the cold reduction parameter from conventional high reduction (>70%) to low reduction (10-30%), which fundamentally alters the microstructure development and crystallographic texture formation, thereby achieving both strength and formability

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If high final cold reduction is applied to obtain recrystallized grain structure, then grain structure is refined, but plastic anisotropy increases leading to roping and earing

Engineering Contradiction:
Improvegrain structureVSAvoidplastic anisotropy
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

By changing the cold reduction parameter to low reduction (10-30%), the patent prevents the formation of highly linear alpha fibers and aligned cube-texture components, thereby eliminating plastic anisotropy and associated defects like roping and earing

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional cold rolling process is used with high reduction, then production efficiency is maintained, but product consistency deteriorates due to anisotropic properties

Engineering Contradiction:
Improveproduction efficiencyVSAvoidproduct consistency
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent changes the cold reduction parameter to low reduction (10-30%), which produces isotropic aluminum alloy sheets with consistent mechanical properties in all directions, thereby improving product consistency while maintaining production efficiency

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

The method produces aluminum alloy sheets with enhanced formability, consistency, and reduced spoilage rates, enabling high-speed commercial manufacture of complex products with improved mechanical properties.

Implementation Method 1

the cold rolling step results in an about 25% to about 70% reduction in thickness

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

The forming process produces a crystallographic texture of an aluminum alloy that promotes plastic anisotropy

Methodology Applied
Scientific EffectCrystallographic texture formation:

Implementation Method 3

Conventional processes for producing aluminum alloy sheets include a cold rolling step to obtain a product having a fully recrystallized grain structure

Methodology Applied
Scientific EffectRecrystallization: Annealing

Data Source

PatentEP4234752B1Methods of making highly-formable aluminum alloys and aluminum alloy products thereof
Publication Date: 2025.06.25 NOVELIS INC(US)
  • EP4234752B1 patent drawingFigure 1A~2
  • EP4234752B1 patent drawingFigure 3~4
  • EP4234752B1 patent drawingFigure 5~6

AI summary

Provided herein are highly-formable aluminum alloys and methods of making such alloys. The method of preparing aluminum alloys described herein can include a low final cold reduction step and/or an optional inter-annealing step to produce randomly distributed crystallographic texture components that produce an isotropic aluminum alloy product exhibiting improved formability and deep drawability. The methods described herein result in aluminum alloy microstructures having a balance of alpha fibers and beta fibers that promote improved formability of aluminum alloy sheets. The resulting improvements in quality allow for shaping processes with reduced rates of spoilage.