Aluminum Brazing Sheet Interliner for Heat Exchanger Corrosion Resistance
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Solution Overview
Problem
Plate-type heat exchangers face challenges in achieving acceptable corrosion resistance, particularly at joints and through the thickness of the sheet material, which affects their durability and performance.
Innovation Solution
A brazing sheet comprising a core layer, a brazing layer, and an interliner layer is developed, where the core layer is at least partially recrystallized, the brazing layer is made of a 4XXX series aluminum alloy, and the interliner layer is unrecrystallized, with specific compositions and thicknesses to enhance corrosion resistance and formability, and is formed through homogenization and hot rolling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional brazing sheet structure is used, then manufacturing simplicity is maintained, but corrosion resistance at joints and through thickness is insufficient
Solution Approach 1:
The brazing sheet is divided into three distinct layers: a core layer (aluminum or aluminum alloy), a brazing layer (4XXX series aluminum alloy with 5-15% Si), and an interliner layer (3XXX series aluminum alloy with Mn, Mg, and Si). This segmentation allows each layer to perform its specific function - the core provides structural integrity, the brazing layer enables reliable joining, and the interliner enhances corrosion resistance by controlling liquid film migration during brazing.
Solution Approach 2:
The invention uses a composite structure combining different aluminum alloys with specific compositional ranges. The core layer uses 1XXX or 3XXX series, the interliner uses 3XXX series with specific Mn (0.5-3.0%) and Mg (0.1-1.0%) content, and the brazing layer uses 4XXX series with 5-15% Si. This composite approach optimizes both corrosion resistance and brazing performance.
2Duration of action of stationary object
If the brazing sheet is designed for high corrosion resistance, then durability is improved, but manufacturing complexity increases
Solution Approach 1:
The invention specifies precise compositional parameters for each layer to achieve the desired balance. The interliner layer contains 0.5-3.0% Mn and 0.1-1.0% Mg, which are critical for preventing liquid film migration. The brazing layer contains 5-15% Si for optimal brazing performance. These parameter ranges enable manufacturers to produce sheets with improved durability using standard aluminum alloy processing techniques.
Solution Approach 2:
The interliner layer is positioned between the core and brazing layers before the brazing process occurs. This preliminary configuration ensures that during brazing, the interliner controls liquid film migration and protects the core layer, thereby pre-establishing corrosion resistance before the final product is assembled.
3Reliability
If the interliner layer composition is optimized for corrosion resistance, then liquid film migration is reduced, but material selection complexity increases
Solution Approach 1:
The interliner layer has a specific local composition optimized for its function: 3XXX series aluminum alloy with 0.5-3.0% Mn, 0.1-1.0% Mg, and 0.01-0.5% Si. This localized compositional optimization ensures the interliner effectively controls liquid film migration at the interface between the core and brazing layers, while the rest of the brazing sheet can be tailored for other requirements.
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 solution provides improved corrosion resistance and formability, reducing liquid film migration and maintaining structural integrity, while allowing for efficient brazing processes like controlled atmospheric brazing or vacuum brazing.
Implementation Method 1
The core layer comprises a first aluminum alloy having a first recrystallization temperature
Implementation Method 2
The first part is coupled to the second part by a process comprising at least one of controlled atmospheric brazing and vacuum brazing
Data Source
AI summary
Brazing sheets, articles formed from or including all or a portion of brazing sheets, and methods of forming articles are provided. A brazing sheet comprising a core layer, a brazing layer, and an interliner layer intermediate the core layer and the brazing layer. The core layer comprises a first aluminum alloy having a first recrystallization temperature. The interliner layer comprises a 3XXX series aluminum alloy having a second recrystallization temperature greater than the first recrystallization temperature. The 3XXX series aluminum alloy comprises, in weight percentages based on total weight of the 3XXX series aluminum alloy: 0.01 to 0.2 silicon; 0 to 0.6 copper; 0.8 to 1.9 manganese; 0 to 0.2 chromium; 0 to 0.15 zirconium; 0 to 0.4 iron; 0 to 3 zinc; 0 to 0.2 magnesium; 0 to 0.3 titanium; 0 to 0.1 vanadium; 0 to 0.5 bismuth; aluminum; and impurities.