Al Alloy Joined Body Single-Step Aging
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Solution Overview
Problem
Conventional Al-Zn-Mg series alloys face challenges in achieving high strength and weight reduction while maintaining hardness recovery performance after welding, due to complex and time-consuming heat treatment processes, which hinder productivity and weight savings.
Innovation Solution
A method involving a single-step aging treatment and optimized alloy composition (Fe: 0.2-0.35%, Cu: 0.1-0.4%, Mn: 0.3-0.6%, Mg: 2.0-2.5%, Zn: 5.0-5.5%, Zr: 0.1-0.2%, Ti: 0.2% or less) for producing Al alloy joined bodies, allowing for efficient production of high-strength, lightweight products with improved mechanical characteristics and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional two-step aging treatment is performed to secure sufficient strength, then tensile strength and hardness are improved, but production time and process complexity increase significantly
Solution Approach 1:
The patent combines the two separate aging treatments (first aging at 80-130°C for 1-16 hours and second aging at 140-190°C for 2-24 hours) into a single integrated aging treatment step. The alloy is aged at 140-190°C for 2-24 hours in one continuous process, eliminating the need for intermediate cooling and transfer operations while achieving the same strength enhancement through optimized temperature-time parameters.
Solution Approach 2:
The patent modifies the aging treatment parameters by performing aging at higher temperatures (140-190°C) for shorter durations compared to conventional methods. This parameter optimization allows achieving sufficient precipitate formation and strength enhancement in a single step rather than requiring two sequential steps with lower temperatures and longer cumulative times.
2Strength
If conventional two-step aging treatment is performed to secure sufficient strength, then hardness recovery performance is improved, but process complexity increases
Solution Approach 1:
The patent merges two distinct heat treatment processes into one unified aging treatment operation. Instead of requiring separate furnaces or treatment zones for first and second aging steps, the invention implements a single aging process that achieves both strength enhancement and hardness recovery simultaneously, thereby simplifying the overall heat treatment system and operational procedures.
Solution Approach 2:
The patent extracts and eliminates the unnecessary intermediate step between aging treatments. By removing the first aging step and its associated cooling and transfer operations, the process complexity is reduced while the essential functions of strength enhancement and hardness recovery are maintained through the optimized single aging treatment parameters.
3Strength
If alloy thickness is increased to compensate for strength loss after welding, then strength is maintained, but weight reduction goals are compromised
Solution Approach 1:
The patent changes the material parameters by optimizing the alloy composition (Al-Zn-Mg series with specific ranges of Zn, Mg, and trace elements) and heat treatment parameters (single aging at 140-190°C). These parameter optimizations enhance the alloy's inherent strength and hardness recovery characteristics, allowing thinner sections to achieve the required strength levels without increasing weight.
Solution Approach 2:
The patent improves the microstructural characteristics of the alloy, creating a more uniform and fine-grained precipitate distribution throughout the matrix. This refined microstructure enhances the alloy's mechanical properties at the microscopic level, enabling strength to be achieved through material quality rather than increased thickness, thus maintaining weight reduction benefits.
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 enables the production of Al alloy joined bodies with high strength and desired mechanical characteristics, reduced weight, and excellent hardness recovery performance after welding, while simplifying the aging treatment process and enhancing productivity.
Implementation Method 1
the welded portion will re-solution treated due to the welding heat to be softened once, but the subsequent natural aging causes resumption of the strength
Implementation Method 2
it is known that the tensile strength and hardness can be increased and the stress corrosion cracking property can be improved by performing artificial aging after leaving a quenched alloy at room temperature for 24 hours or more after the quenching treatment
Implementation Method 3
the subsequent natural aging causes resumption of the strength
Implementation Method 4
performing artificial aging after leaving a quenched alloy at room temperature for 24 hours or more after the quetching treatment
Implementation Method 5
a so-called two-step aging treatment is conducted, wherein a first aging treatment is performed at 80 to 130 °C for 1 to 16 hours and thereafter a second aging treatment is performed at 140 to 190 °C for 2 to 24 hours
Data Source
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AI summary
A method for efficiently producing a strong and light Al alloy joined body is provided. The method for producing an Al alloy joined body of the present invention includes a step of obtaining an Al alloy melt having a predetermined alloy composition, a step of obtaining an Al alloy ingot having a predetermined composition by continuously casting the Al alloy melt, a step of obtaining an Al alloy cast member by subjecting the Al alloy ingot to a homogenization treatment, a step of obtaining an Al alloy forged member by subjecting the Al alloy cast member to hot forging, a step of subjecting the Al alloy forged member to a solution heat treatment, a step of subjecting teal alloy forged member after the solution heat treatment to a single-step aging treatment, and a step of obtaining an Al alloy joined body by welding the Al alloy forged member after the single-step aging treatment with an Al alloy component to be joined.