Copper-Based Brazing Alloy for Induction Joining of Stainless Exhaust Parts
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Solution Overview
Problem
Current brazing materials for induction brazing of exhaust system components in motor vehicles lack sufficient oxidation and corrosion resistance, and are not suitable for automated production due to poor wetting behavior and deformability, especially when used with stainless steel.
Innovation Solution
A copper-based brazing material with specific alloy compositions, including nickel, zinc, manganese, chromium, silicon, and molybdenum, which provides improved oxidation and corrosion resistance, deformability, and suitable processing temperatures for induction brazing, ensuring good wetting and high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel-based brazing materials are used to achieve sufficient wetting and gap filling, then wetting behavior is improved, but deformability deteriorates and the material can only be produced as powders or amorphous thin films
Solution Approach 1:
The invention uses a composite material consisting of a nickel-based brazing alloy combined with a copper-based deformation layer. This composite structure allows the nickel component to provide excellent wetting behavior while the copper component provides deformability, enabling the material to be formed into wires and other shapes suitable for automated induction brazing.
Solution Approach 2:
The brazing material is segmented into functionally distinct layers: a nickel-rich brazing alloy layer that provides wetting and gap-filling properties, and a copper-based deformation layer that provides deformability. This segmentation allows each layer to optimize its specific function without compromising the other.
2Ease of manufacture
If copper alloys are used to provide good deformability and wetting, then ease of manufacture is improved, but oxidation resistance at high temperatures deteriorates
Solution Approach 1:
The invention creates a composite structure where the copper-based deformation layer provides deformability and the nickel-based brazing alloy layer provides oxidation resistance. The nickel layer acts as a protective barrier against oxidation while the copper layer maintains good formability and wetting characteristics.
Solution Approach 2:
Different regions of the brazing material have different properties optimized for their specific functions: the copper-based deformation layer has high deformability and wetting properties, while the nickel-based brazing alloy layer has high oxidation resistance. This local quality differentiation resolves the contradiction between deformability and oxidation resistance.
3Strength
If arc welding is used to join exhaust system components, then joint strength is improved, but applicability to thin-walled components deteriorates
Solution Approach 1:
The invention replaces the arc welding process with induction brazing. Instead of using high-energy arc welding that is difficult to control on thin-walled components, the patent uses induction heating to melt the brazing material, which then flows into the joint by capillary action. This substitution of the joining mechanism allows for effective joining of thin-walled exhaust components while maintaining joint 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 brazing material achieves excellent wetting, high-temperature resistance, and mechanical strength, with a melting point below 1150°C, allowing for efficient and reliable induction brazing of stainless steel components in exhaust systems without cracking or corrosion, meeting the requirements for automotive applications.
Implementation Method 1
induction brazing has the advantage that the heating phase can be performed locally and with great speed and good reproducibility
Implementation Method 2
The brazing material used has to guarantee sufficient wetting of the substrate's surface and gap filling during the brazing process
Data Source
AI summary
A copper-based brazing material comprises an alloy having nickel in a proportion of from 20 to 35 percent by weight, zinc in a proportion of from 5 to 20 percent by weight, manganese in a proportion of from 5 to 20 percent by weight, chromium in a proportion of from 1 to 10 percent by weight, silicon in a proportion of from 0.1 to 5 percent by weight and molybdenum in a proportion of from 0 to 7 percent by weight, each based on the total weight of the alloy, and the remainder being copper and unavoidable impurities. The alloy is in particular free from boron, phosphorus and lead. The brazing material can be used for induction brazing of components made of iron materials for exhaust systems in motor vehicles.