Aluminum Alloy Deep Drawing With Ultra-Low Temperature Gradient
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Solution Overview
Problem
The existing methods for forming deep-cavity thin-walled curved aluminum alloy parts face challenges such as cracking, uneven deformation, and microstructure impairment due to poor plasticity and low work hardening ability, especially in hot drawing processes, which result in low yield and poor quality of finished products.
Innovation Solution
The method involves ultra-low temperature gradient drawing, where an aluminum alloy sheet is cooled to an ultra-low temperature in the die cavity zone while the flange zone remains at a higher temperature, using mediums like liquid argon or nitrogen to control formability and flow stress, thereby improving deformation resistance and strain hardening index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If room temperature deep drawing is used for aluminum alloy thin-walled curved parts, then the process is simple, but the material's poor plasticity causes cracking in transition fillet and suspended zones
Solution Approach 1:
The patent applies temperature parameter changes by cooling the die cavity zone to ultra-low temperature (−180℃ to −270℃) while keeping the flange zone at room temperature or higher. This creates a temperature gradient that fundamentally changes the material's plasticity characteristics in different zones, allowing deep drawing of complex shapes without cracking.
Solution Approach 2:
The patent implements local quality by creating different temperature conditions in different zones of the workpiece. The die cavity zone is cooled to ultra-low temperature to improve plasticity where deformation occurs, while the flange zone remains at higher temperature to maintain formability, achieving zone-specific material properties.
2Reliability
If hot drawing is used to improve formability, then deep-cavity parts can be formed, but concentrated deformation in suspended zone causes uneven deformation and cracking
Solution Approach 1:
The patent applies local quality by creating a temperature gradient where only the die cavity zone is cooled to ultra-low temperature while the flange zone remains at higher temperature. This localized cooling improves plasticity precisely where needed for deep drawing while maintaining formability in the flange zone, preventing concentrated deformation.
Solution Approach 2:
The patent segments the temperature field into different zones: the die cavity zone is cooled to ultra-low temperature to improve plasticity for deep drawing, while the flange zone is kept at higher temperature to maintain formability. This spatial segmentation of temperature conditions resolves the contradiction between formability and deformation uniformity.
3Strength
If hot drawing with subsequent quenching is used to control microstructure, then material strength can be improved, but serious deformation and surface scratches occur
Solution Approach 1:
The patent applies preliminary action by performing ultra-low temperature deep drawing first to achieve the desired complex shape with high precision, and then applying artificial aging treatment to improve strength. This sequence avoids the problems of quenching after forming, as the shape is already finalized before strength enhancement.
Solution Approach 2:
The patent inverts the conventional sequence of operations: instead of forming first at high temperature then quenching to improve strength (which causes deformation), it forms at ultra-low temperature to achieve precise shape first, then applies aging treatment to improve strength without affecting the already-formed geometry.
4Reliability
If multi-pass drawing and intermediate annealing are used to improve formability, then deep-cavity parts can be formed, but yield is low and quality is poor
Solution Approach 1:
The patent applies parameter changes by using ultra-low temperature (−180℃ to −270℃) in the die cavity zone to fundamentally improve the aluminum alloy's plasticity. This single parameter change enables one-pass forming of deep-cavity parts without requiring multi-pass drawing or intermediate annealing, thereby improving both productivity and quality.
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 approach significantly enhances the formability and strain hardening of aluminum alloy sheets, preventing cracking and ensuring uniform deformation, while reducing heat consumption and avoiding microstructure impairment, leading to improved forming quality and reduced wall thickness variation.
Implementation Method 1
forming an ultra-low temperature gradient in which the temperature of the die cavity zone is lower than the temperature in the flange zone
Implementation Method 2
filling a cavity of a die shoe with an ultra-low temperature medium to cool a die cavity zone of the aluminum alloy sheet
Data Source
AI summary
The present invention provides a method for forming an aluminum alloy thin-walled curved part by ultra-low temperature gradient drawing. This method includes: placing the aluminum alloy sheet on a die, and closing a blank holder to hold the aluminum alloy sheet in a flange zone; filling a cavity of a die with an ultra-low temperature medium to cool a die cavity zone of the aluminum alloy sheet to a set low temperature, and forming an ultra-low temperature gradient in which the temperature of the die cavity zone is lower than the temperature in the flange zone; applying a set blank holder force to the blank holder, and controlling a punch to move downwards to form a deep-cavity thin-walled curved part; and controlling the punch to move upwards, opening the blank holder, and taking out the formed deep-cavity thin-walled curved part.