Shaped Metal Container Annealing for Non-Cylindrical Forming
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Solution Overview
Problem
Existing methods for producing metal containers with non-cylindrical shapes, such as those mimicking glass or plastic bottles, face challenges due to work hardening issues that limit ductility and elongation, making it difficult to achieve desired shapes without increasing hardness and reducing forming capabilities.
Innovation Solution
An annealing process is applied to metal container preforms at elevated temperatures to reduce yield strength and increase ductility, allowing for more elongation before failure, and localized heating techniques like induction annealing are used to maintain material properties in specific sections, enabling the formation of complex shapes without excessive work hardening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If deep drawing and wall ironing processes are used to produce metal containers with non-cylindrical shapes, then the container can achieve complex shapes, but the work hardening increases hardness significantly and reduces ductility and elongation
Solution Approach 1:
The patent applies annealing heat treatment to change the physical state of the metal material, reducing its hardness and increasing ductility. By controlling temperature parameters (heating to annealing temperature and maintaining it), the material properties are modified to enable complex shaping without excessive work hardening
Solution Approach 2:
The annealing process is performed as a preliminary action before the deep drawing and wall ironing operations. This pre-treatment softens the material in advance, preparing it for subsequent forming operations that would otherwise cause excessive work hardening and reduce formability
2Length of moving object
If multiple re-draw operations are performed to achieve tall containers with high height/diameter ratio, then the container height increases, but the work hardening accumulates and reduces available elongation
Solution Approach 1:
Annealing is performed as a preliminary treatment before the drawing operations to restore ductility and prevent accumulation of work hardening during multiple re-draw steps, enabling achievement of tall container dimensions while maintaining material formability
Solution Approach 2:
The patent employs periodic annealing during the multi-step drawing process to intermittently reset the material properties. This periodic heat treatment removes accumulated work hardening and restores ductility, allowing the process to continue through multiple drawing stages to achieve high height/diameter ratios
3Manufacturing precision
If wall ironing is used to control body wall thickness, then thickness distribution can be precisely controlled, but the massive work hardening increases hardness to 650 MPa or more and reduces forming capability
Solution Approach 1:
Annealing heat treatment is applied to change the material parameters (hardness, ductility) after wall ironing, reducing the excessive hardness caused by massive work hardening and restoring forming capability for subsequent operations
Solution Approach 2:
The patent integrates annealing as a continuous or intermediate step within the manufacturing sequence, ensuring that material properties are continuously optimized for each subsequent forming operation, maintaining formability throughout the multi-step process while achieving precise thickness control
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 softens the metal, allowing for more complex shapes and reduced material stress, enabling the production of metal containers with increased formability and reduced hardness, which can mimic non-cylindrical shapes while maintaining strength and usability.
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 softens the metal, allowing for more complex shapes and reduced material stress
Implementation Method 3
localized heating techniques like induction annealing are used to maintain material properties in specific sections
Data Source
Figure 1A~1D
Figure 2A~3C
Figure 4A~4K
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.