Shaped Metal Container Annealing for Rounded Grain Formability
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Solution Overview
Problem
Current methods for producing metal containers, such as deep drawing and wall ironing, result in work hardening, which limits the elongation and formability of metal due to increased hardness, making it difficult to create shaped containers with non-circular bodies or tailored shapes like glass or plastic bottles.
Innovation Solution
An annealing process is applied to metal container preforms at elevated temperatures to reduce yield strength and increase ductility, creating a rounded grain structure that allows for more elongation and formability, enabling the production of shaped metal containers with varying diameters and complex shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If deep drawing and wall ironing methods are used to produce metal containers, then the container strength is improved, but the metal work hardening increases which limits further elongation and formability
Solution Approach 1:
The patent applies intermediate annealing treatments during the forming process to change the material parameters (hardness, ductility) of the metal preform. By controlling the annealing temperature and duration, the metal's crystal structure is modified to restore ductility after work hardening, enabling multiple forming operations to achieve complex shapes that would otherwise be impossible with traditional continuous drawing methods
2Length of moving object
If multiple re-draw operations are performed to achieve tall containers with high height/diameter ratio, then the container height is increased, but the number of manufacturing steps and production time increase
Solution Approach 1:
The patent performs preliminary annealing treatment on the metal preform before the forming operations. This preliminary action softens the material and increases its ductility, allowing the metal to be drawn into tall container shapes with high height/diameter ratios in fewer steps, thereby reducing overall production time while achieving the desired container dimensions
3Productivity
If traditional deep drawing methods are used, then cylindrical containers can be produced efficiently, but shaped containers with non-circular bodies or tailored shapes cannot be produced
Solution Approach 1:
The patent utilizes annealing treatment to change the material parameters of the metal preform, specifically increasing ductility and reducing flow stress. This parameter change enables the metal to be formed into complex non-circular shapes and tailored profiles that would otherwise require excessive force or multiple operations, thus maintaining production efficiency while dramatically increasing shape variety
4Strength
If work hardening is increased to strengthen the container wall, then the container strength is improved, but the elongation percentage and available forming capability are reduced
Solution Approach 1:
The patent applies intermediate annealing treatments that temporarily change the material parameters by reducing hardness and increasing ductility. This allows the metal to undergo further plastic deformation and elongation during subsequent forming operations. After the final forming is complete, the metal naturally work hardens again during cooling, providing the necessary wall strength for the finished container
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 annealing process reduces metal hardness, increases ductility, and allows for the production of shaped metal containers with up to 18% elongation, enabling the creation of complex shapes that were previously difficult or impossible with traditional methods, while also reducing metal usage by at least 10% and lowering production costs.
Implementation Method 1
An annealing process is applied to metal container preforms at elevated temperatures to reduce yield strength and increase ductility
Implementation Method 2
The annealing process reduces metal hardness, increases ductility, and allows for the production of shaped metal containers with up to 18% elongation, enabling the creation of complex shapes
Data Source
AI summary
The principles of the present invention further provide both a shaped metal container and its preforms that exhibit a rounded grain structure characteristic created by an annealing process and a method for making a shaped metal container. The process of making said metal container results in a quicker process time and uses less metals (at least 10% metal weight savings), thus allowing for a decrease in the costs of making such shaped metal containers. A shaped metal container may include work hardened rolled sheet-metal defining a sidewall, an opening, and a base, where at least one section along the sidewall has grains with an average aspect ratio less than about 4 to 1.