Electric Induction Brazing in Inert Atmosphere
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Solution Overview
Problem
Conventional copper brazing methods face issues such as distortion, high gas consumption, high operating costs, batching of parts, manual fixturing, quality inconsistencies, and excessive flux usage, particularly in furnace and torch-based processes.
Innovation Solution
Electric induction brazing using a substantially oxygen-free copper alloy filler or preform in an inert gas atmosphere within a minimally sized joint brazing chamber, facilitated by an induction coil, which localizes heat application and eliminates the need for flux, allowing for high tensile strength joints with reduced distortion and lower gas usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If furnace brazing is used to join copper alloy parts, then the brazing can be performed in a controlled atmosphere, but the entire part is heated causing distortion and annealing in undesirable regions
Solution Approach 1:
The patent applies induction heating to locally heat only the joint region rather than the entire part. The induction coil is positioned to concentrate electromagnetic energy at the specific brazing location, creating a localized thermal zone that melts the filler metal while leaving the rest of the part at ambient temperature, thus preventing distortion and unwanted annealing.
Solution Approach 2:
The patent replaces the conventional furnace heating system with an induction heating system. Instead of using thermal radiation and convection from a furnace environment, the invention uses electromagnetic induction to directly generate heat at the joint region through eddy currents in the workpiece, achieving precise thermal control without the drawbacks of furnace brazing.
2Ease of operation
If torch brazing is used for copper alloy parts, then the process is flexible and portable, but manual fixturing and inconsistent quality occur
Solution Approach 1:
The induction heating system is self-regulating through electromagnetic coupling. The workpiece itself serves as the heating element through induced eddy currents, automatically concentrating heat where the coil is positioned without requiring manual adjustment of flame or temperature control by the operator, thereby ensuring consistent quality.
Solution Approach 2:
The patent replaces the manual torch system with an automated induction heating system. The electromagnetic field automatically delivers controlled energy to the joint region, eliminating the variability introduced by manual flame control and positioning, while maintaining the flexibility of localized heating.
3Reliability
If conventional copper brazing is performed, then the joint can be formed, but high gas consumption and high operating costs result
Solution Approach 1:
The patent uses a minimal inert gas atmosphere (such as nitrogen or argon) contained only around the joint region during induction brazing, rather than requiring a full furnace atmosphere. This dramatically reduces gas consumption while still protecting the molten filler metal from oxidation, lowering operating costs.
Solution Approach 2:
The patent replaces fuel-based heating (gas or oil burners) with electric induction heating. The induction system converts electrical energy directly into heat at the joint region with high efficiency, eliminating the need for large volumes of combustion gas and reducing both direct gas consumption and associated energy losses.
4Productivity
If furnace brazing is used for copper alloy parts, then batch processing can be performed, but batching of parts without one piece flow occurs
Solution Approach 1:
The induction brazing system is designed as a modular, localized process that can be integrated into a continuous production line. Each brazing station is independent and self-contained, allowing parts to flow through the system one at a time or in small batches without requiring complex batch loading and unloading mechanisms, thus enabling one-piece flow while maintaining productivity.
5Reliability
If conventional brazing is performed, then the joint can be formed, but excessive flux usage and dirty parts result
Solution Approach 1:
The patent employs a controlled inert gas atmosphere around the joint region during induction brazing, which prevents oxidation of the copper alloy filler metal and base metals. This eliminates or minimizes the need for flux, resulting in clean parts without excessive flux consumption and associated waste.
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 achieves high tensile strength brazed joints with localized heat application, minimizing part distortion, reducing gas consumption, and enabling a one-piece flow process, resulting in clean, cost-effective, and consistent brazing with low flux usage.
Implementation Method 1
electric induction brazing
Implementation Method 2
supplying alternating current to ring induction coil 118 in the brazing box, induction brazes the end cap fitting 112 to end 102a of tube 102
Implementation Method 3
Establishing a nitrogen atmosphere in the brazing box from a supply of nitrogen
Data Source
AI summary
Apparatus and method are provided for an electric induction brazing process in an inert atmosphere using a substantially oxygen-free copper alloy filler or preform under an inert atmosphere within a brazing chamber minimally sized for containment of the brazed joint region and an induction coil. The inert atmosphere may be nitrogen gas supplied from a liquid nitrogen source. For brazing of an open-interior fitting around a hole in a tubular material a nesting area is provided around the hole for seating of the filler or preform and the fitting.