Corrosion-Resistant Brazing Sheet Package with Zinc Cladding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metal tubing used in heat exchangers is prone to corrosion and is expensive to produce due to inconsistent zinc coverage, and exhibits softness in the post-braze condition.
Innovation Solution
A multi-layer metal sheet with a core layer of aluminum-containing alloy and cladding layers comprising zinc, which forms a sacrificial dense precipitate band for enhanced corrosion resistance and mechanical properties, preventing perforation and improving corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure zinc spray coating is applied to microport extrusions, then corrosion resistance is improved, but manufacturing cost increases and zinc coverage consistency deteriorates
Solution Approach 1:
The invention uses a composite multi-layer metal sheet structure consisting of an aluminum-containing alloy core layer (with 0.1-0.2 wt% Ti) bonded to zinc-containing cladding layers (with 2.5-4.0 wt% Zn). This composite structure provides consistent corrosion protection through the zinc-rich cladding layers while avoiding the high costs and inconsistency issues of spray coating processes.
2Reliability
If pure zinc spray coating is applied to microport extrusions, then corrosion resistance is improved, but manufacturing precision deteriorates due to inconsistent zinc coverage
Solution Approach 1:
The bonded multi-layer sheet with zinc-containing cladding layers provides uniform and consistent zinc distribution throughout the product, eliminating the coverage inconsistency inherent in spray coating methods. The cladding layers are metallurgically bonded to the core layer, ensuring consistent protection.
Solution Approach 2:
The invention specifies precise compositional parameters for the core layer (0.1-0.2 wt% Ti, specific Si, Fe, Cu, Mn, Mg content) and cladding layers (2.5-4.0 wt% Zn, specific Si content), which when controlled during manufacturing, ensure consistent material properties and corrosion resistance across all products.
3Ease of manufacture
If conventional aluminum alloy is used without titanium, then manufacturing cost is reduced, but mechanical strength deteriorates in post-braze condition
Solution Approach 1:
The invention adds a specific small amount of titanium (0.1-0.2 wt%) to the aluminum-containing alloy core layer. This parameter change dramatically improves post-braze mechanical strength and hardness without significantly increasing manufacturing cost, as titanium is added in trace amounts during the alloying process.
Solution Approach 2:
The titanium is strategically added to the core layer to create local strengthening effects, particularly at the interfaces with the cladding layers. This localized quality improvement enhances overall mechanical strength where it is most needed in the post-braze condition.
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 multi-layer metal sheet effectively prevents corrosion and maintains mechanical strength, as demonstrated by resistance to acid immersion and accelerated airside corrosion tests, with no perforation after extended testing periods.
Implementation Method 1
a first cladding layer comprising from 2.5 wt % to 4.0 wt % of zinc; and a second cladding layer comprising from 2.5 wt % to 4.0 wt % of zinc... forms a sacrificial dense precipitate band for enhanced corrosion resistance
Implementation Method 2
The multi-layer metal sheet effectively prevents corrosion and maintains mechanical strength, as demonstrated by resistance to acid immersion and accelerated airside corrosion tests, with no perforation after extended testing periods
Data Source
AI summary
This application discloses a corrosion-resistant brazing sheet package for use in manufacturing tubing. The brazing sheet package includes a core layer of aluminum-containing alloy comprising from 0.1 wt % to 0.2 wt % of titanium. The core layer has a first side and a second side. The first side of the core layer is adjacent to a first cladding layer to form a first interface. The second side of the core layer is adjacent to a second cladding layer to form a second interface. The first cladding layer and the second cladding layer each include from 2.5 wt % to 4.0 wt % of zinc.