Aluminum Alloy Brazing Sheet for Uniform Flux-Free Fillet Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for brazing aluminum alloys without flux in an inert gas atmosphere face challenges such as inferior fillet formation and high maintenance costs due to the need for expensive vacuum equipment and difficulties in exposing the molten brazing material's surface effectively, leading to distorted or incomplete joints.
Innovation Solution
An aluminum alloy brazing sheet with a core material and a brazing material containing Si and specific atoms like Mg, Li, Be, Ca, Ce, La, Y, and Zr, which form oxide particles with a volume change ratio of 0.99 or lower, allowing for effective exposure of the molten brazing material's surface during brazing heating in an inert gas atmosphere without flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flux is used in a nitrogen gas furnace to break the oxide film, then the oxide film can be effectively broken, but the cost of flux and the cost of the process of applying the flux increase
Solution Approach 1:
The invention extracts and eliminates the flux component from the brazing system by using a brazing material containing Mg that can break the oxide film through vaporization and reaction during heating, thereby removing the need for separate flux application processes and reducing manufacturing costs
Solution Approach 2:
The brazing material contains Mg that automatically breaks the oxide film through vaporization and chemical reaction during the brazing heating process itself, making the oxide film breaking function self-contained within the brazing material rather than requiring external flux
2Reliability
If a brazing material formed of Al—Si—Mg based alloy is used in a vacuum heating furnace, then the oxide film can be broken by vaporized Mg, but expensive vacuum heating equipment is required and high maintenance cost is needed to remove Mg adhering to the inside of the furnace
Solution Approach 1:
The invention uses a nitrogen gas atmosphere instead of vacuum for heating, allowing the brazing material to break the oxide film through Mg vaporization while avoiding the need for expensive vacuum equipment and its associated maintenance requirements
Solution Approach 2:
The invention accepts that Mg will vaporize and adhere to the furnace interior as a temporary, manageable issue rather than requiring expensive vacuum equipment, treating the Mg adhesion as a short-term problem that can be cleaned during routine maintenance
3Reliability
If Mg is included in a brazing material to enable surface joining, then the oxide film can be broken, but the oxide film is divided into particles and a newly formed surface is exposed by external force, causing formation of a distorted fillet in a practical joint
Solution Approach 1:
The invention changes the parameters of the brazing material by specifying precise Si content (4.0-13.0 mass%) and Mg content (0.01-2.0 mass%), along with controlled oxide film thickness (5-30 nm), to achieve uniform fillet formation without distortion while maintaining effective oxide film breaking
Solution Approach 2:
The invention creates a composite brazing material system combining Al-Si-Mg alloy with controlled oxide film and specific additive elements (Ca, Ce, La, Y, Zr, Be) to achieve both effective oxide film breaking and uniform fillet formation that neither component could achieve alone
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 enables excellent brazability by ensuring uniform exposure of the brazing material's surface, resulting in high-quality joints with improved corrosion resistance and reduced maintenance costs, as the oxide particles effectively break the oxide film without the need for flux or expensive vacuum equipment.
Implementation Method 1
Mg in the brazing material is vaporized by heating in vacuum, to break the oxide film on the surface of the material
Implementation Method 2
the vaporized Mg adheres to the inside of the furnace
Implementation Method 3
flux reacts with an oxide film during brazing heating, and breaks the oxide film
Data Source
AI summary
An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using flux includes a core material of aluminum or aluminum alloy, and a brazing material of aluminum alloy including Si of 4.0 mass % to 13.0 mass % and cladding one side surface or both side surfaces of the core material. One or both of the core material and the brazing material includes any one or two or more types of X atoms (X is Mg, Li, Be, Ca, Ce, La, Y, and Zr). The aluminum alloy brazing sheet is a brazing sheet in which oxide particles including the X atoms and having a volume change ratio of 0.99 or lower with respect to an oxide film before brazing heating are formed on a surface thereof, by brazing heating.