Copper-Phosphorus Brazing Wire for Fine Spectacle Frame Joining
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Solution Overview
Problem
Existing copper-phosphorus brazing filler metals have a large amount of brittle phase Cu3P, leading to poor processability and difficulty in obtaining fine wires with diameters below 0.5 mm for brazing copper alloy spectacle frames, resulting in defects such as air holes and reduced mechanical properties.
Innovation Solution
A copper-phosphorus brazing wire with a composition of 87.1%˜91.4% Cu, 1.5%˜2.6% Ag, 5.9%˜8.4% P, and 0.8%˜1.68% Si, along with a preparing method involving electromagnetic induction heating and differential rotating speeds of pulleys to achieve a diameter below 0.5 mm, and a system incorporating a first alloy wire preparing unit and a drawing unit for efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-phosphorus brazing filler metal is used to reduce cost and achieve moderate brazing temperature, then cost is reduced and brazing temperature is moderate, but the filler metal contains a large amount of brittle phase Cu3P leading to poor processability and difficulty in obtaining fine wires below 0.5 mm diameter
Solution Approach 1:
The patent changes the chemical composition parameters of the brazing filler metal by adding specific amounts of Si (0.01-3 wt%) and Al (0.01-1 wt%) elements to modify the phase structure. This parameter change reduces the content of brittle Cu3P phase and promotes formation of eutectic structures, thereby improving both brazing quality and wire drawing processability simultaneously
Solution Approach 2:
The patent creates a composite microstructure in the brazing filler metal by combining multiple phases including Cu-P eutectic, Cu-Si-Al intermetallic compounds, and modified Cu3P phases. This composite structure improves the overall performance by combining the low melting point advantage with enhanced ductility and processability
2Ease of manufacture
If silver brazing filler metal is used to achieve low brazing temperature and easy processing into fine wires, then brazing temperature is low and processability is good, but the high silver content results in high cost and Zn volatilization causes defects reducing joint mechanical properties
Solution Approach 1:
The patent replaces expensive silver with cheaper copper-phosphorus-silicon-aluminum alloy system. Although the base material is less noble, the addition of Si and Al creates protective effects that compensate for the lower intrinsic strength, achieving cost reduction while maintaining acceptable joint reliability
Solution Approach 2:
The Si and Al elements act as intermediary substances that form protective oxide films and modify the brazing chemistry. These intermediaries prevent Zn volatilization and improve joint quality, allowing the use of lower-cost copper-phosphorus base material while achieving reliability comparable to or better than silver-based fillers
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 achieves a welding effect with low impurity content and high joint strength by forming a dense oxide film, reducing defects and improving mechanical properties, while efficiently producing thin copper-phosphorus brazing wires with a yield over 90%.
Implementation Method 1
continuously performing electromagnetic induction heating treatment on the first alloy wire between the first step pulley and the second step pulley
Data Source
AI summary
The present disclosure relates to the field of brazing material technologies, and particularly to a copper-phosphorus brazing wire for brazing a copper alloy spectacle frame as well as a preparing method and system thereof. The copper-phosphorus brazing wire for brazing a copper alloy spectacle frame includes components with following mass percentage, 87.1%˜91.4% of Cu, 1.5%˜2.6% of Ag, 5.9%˜8.4% of P, 0.2%˜0.42% of Al and 0.8%˜1.68% of Si. For the copper-phosphorus brazing wire according to the present disclosure, through coordination and cooperation of the components, impurity content is low and joint strength is high in a welding process; a mass ratio of the Si to the Al is a constant value, and a dense oxide film may be formed on a surface of a molten pool to hinder volatilization of Zn in a base material.