Aluminum Multi-Hole Tube Composition for Extrudability and Brazed Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aluminum alloy extruded multi-hole tubes for heat exchangers face challenges in achieving high strength and extrudability due to the addition of elements like Mn and Si, which increase deformation resistance, and the manufacturing process is hindered by excessive pressure during extrusion, leading to reduced productivity.
Innovation Solution
The solution involves specifying the content ranges of Mn and Si, with a ratio of 2.6 to 4.0, and employing a two-step homogenization treatment to precipitate fine AlMnSi compounds, followed by hot extrusion at controlled temperatures to maintain strength and improve extrudability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Mn and Si are added in high concentrations to increase strength, then the strength of the aluminum alloy is improved, but the deformation resistance increases and extrudability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing homogenization treatment before extrusion to precipitate fine AlMnSi compounds in advance. This preliminary precipitation reduces the solid solution content of Mn and Si in the aluminum matrix before the extrusion process, thereby lowering deformation resistance and improving extrudability while maintaining the intended strength benefits of the alloying elements
Solution Approach 2:
The patent applies parameter changes by controlling the heating temperature and time during homogenization treatment to optimize the precipitation behavior of AlMnSi compounds. By adjusting these thermal parameters, the patent achieves the desired balance between precipitating enough compounds to improve extrudability while retaining sufficient solid solution strengthening for final strength
2Device complexity
If the extrusion ratio is increased to produce multi-hole tubes, then the product complexity and functionality are improved, but the pressure during extrusion increases excessively and productivity decreases
Solution Approach 1:
The patent applies preliminary action by performing homogenization treatment before extrusion to precipitate fine AlMnSi compounds in advance. This reduces deformation resistance during extrusion, enabling the production of complex multi-hole tube structures with higher extrusion ratios without excessive pressure buildup, thereby maintaining productivity
Solution Approach 2:
The patent applies local quality by creating a non-uniform distribution of AlMnSi compounds through controlled homogenization treatment. The fine compounds are precipitated in a manner that locally reduces deformation resistance in the matrix, facilitating the extrusion of complex multi-hole geometries while maintaining overall structural integrity
3Strength
If Mn and Si are added to increase strength, then the strength after brazing is improved, but the solid solution increases deformation resistance during hot work
Solution Approach 1:
The patent applies preliminary action by performing homogenization treatment before extrusion to precipitate fine AlMnSi compounds in advance. This preliminary precipitation reduces the solid solution content of Mn and Si in the aluminum matrix before hot extrusion, thereby lowering deformation resistance during hot work while maintaining the intended strength benefits of the alloying elements that will be re-dissolved during brazing
Solution Approach 2:
The patent applies periodic action through the two-stage thermal process: first homogenization treatment at high temperature to dissolve alloying elements, then cooling to precipitate fine AlMnSi compounds, followed by extrusion, and finally brazing heating to re-dissolve the compounds. This periodic transformation between solid solution and precipitation states optimizes both extrudability and final strength
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 results in an aluminum alloy extruded multi-hole tube with excellent extrudability and high strength after brazing, ensuring productivity and performance in heat exchanger applications.
Implementation Method 1
employing a two-step homogenization treatment to precipitate fine AlMnSi compounds
Implementation Method 2
strength change (tensile strength (A) of the aluminum alloy after heating test−tensile strength (B) of the aluminum alloy before heating test) in a heating test at 600° C.±10° C. for 3 minutes
Data Source
AI summary
An aluminum alloy extruded multi-hole tube for a heat exchanger is formed of an aluminum alloy comprising Mn of 0.60 to 1.80 mass % and Si of 0.20 to 0.70 mass %, with the balance being Al and inevitable impurities. The aluminum alloy has a ratio (Mn/Si) of the Mn content to the Si content being 2.6 to 4.0. Strength change (tensile strength (A) of the aluminum alloy after heating test−tensile strength (B) of the aluminum alloy before heating test) thereof in a heating test at 600° C.±10° C. for 3 minutes is −5 MPa or more. The present invention can provide an aluminum alloy extruded multi-hole tube for a heat exchanger having excellent extrudability and high strength after brazing, and a method for manufacturing the same.