Composite brazing flux suitable for copper and aluminum dissimilar metal brazing

A technology of composite brazing flux and dissimilar metals, applied in metal processing equipment, welding equipment, welding media, etc., can solve the problems of long welding time, changes in base metal properties, high brazing temperature, etc., and achieve increased spreading area and active temperature range Decrease and increase the effect of activity

Active Publication Date: 2015-06-17
ZHENGZHOU RES INST OF MECHANICAL ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese invention patent 200610161295.6 discloses a 6063 aluminum alloy NOCLOCK non-corrosion flux gas shielded furnace brazing process, and invention patent 200810236036.4 discloses an aluminum alloy flux formula, but the former uses pure aluminum or 3A21 aluminum alloy solder, The scope of application is narrow, and the brazing temperature is high and the welding time is long, which will easily cause changes in the properties of the base metal; the melting point of the latter is about 500°C, and the brazing temperature is about 550°C; neither of them is suitable for use with zinc-aluminum low-temperature high-strength solder It can be used in conjunction with non-corrosion brazing of copper and aluminum dissimilar metals at a temperature of 490~530°C

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Add 300g of deionized water into a 2L tank, add 320g of aluminum trifluoride, 40g of potassium fluoride, 2g of zinc difluoride, 1g of potassium fluoroborate, 5g of potassium fluorogermanate, 115g of rubidium fluoride, 525g of cesium fluoride until completely mixed uniformly, the mixture was kept at a temperature of 130° C. for 2 hours and then dehydrated to obtain the finished flux. The melting point of the brazing flux is 465°C, coated on the surface of aluminum alloy and copper base metal, brazed with Zn-15Al solder at 510°C under nitrogen protection, and there is no residual aluminum oxide layer at the solder / aluminum alloy interface after brazing , the tensile strength of the joint exceeds 82 MPa.

Embodiment 2

[0014] Take 300g of deionized water in a 2L tank, add 315g of aluminum trifluoride, 35g of potassium fluoride, 2g of zinc difluoride, 1g of potassium fluoroborate, 5g of potassium fluorogermanate, 115g of rubidium fluoride, 535g of cesium fluoride until completely mixed uniformly, the mixture was kept at a temperature of 130° C. for 2 hours and then dehydrated to obtain the finished flux. The melting point of the brazing flux is 470°C, coated on the surface of aluminum alloy and copper base metal, brazed with Zn-15Al solder at 520°C under the protection of nitrogen, and there is no residual aluminum oxide layer on the solder / aluminum alloy interface after brazing , the tensile strength of the joint exceeds 85 MPa.

Embodiment 3

[0016] Take 300g of deionized water in a 2L tank, add 320g of aluminum trifluoride, 45g of potassium fluoride, 2g of zinc difluoride, 2g of potassium fluoroborate, 4g of potassium fluorogermanate, and 115g of rubidium fluoride in sequence under rapid stirring , 520g of cesium fluoride, until completely mixed uniformly, the mixture was kept at a temperature of 130°C for 2 hours and then dehydrated to obtain the finished flux. The melting point of the brazing flux is 475°C, coated on the surface of aluminum alloy and copper base metal, brazed with Zn-15Al solder at 520°C under the protection of nitrogen, there is no residual alumina layer on the solder / aluminum alloy interface after brazing , the tensile strength of the joint is about 86 MPa.

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Abstract

The invention discloses a composite brazing flux suitable for copper and aluminum dissimilar metal brazing. The composite brazing flux comprises 50-55% of cesium fluoride, 30-35% of aluminum fluoride, 3-5% of potassium fluoride, 10-12% of rubidium fluoride, 0.1-1% of potassium fluorogermanate, 0.1-0.5% of zinc difluoro and 0.1-0.5% of potassium fluoborate. The composite brazing flux is formed by preparing seven kinds of fluoride in proportion, and has the advantages of being non-hygroscopic and free of corrosion compared with a traditional chloride brazing flux; compared with a traditional fluoride brazing flux, the composite brazing flux obviously narrows the activity temperature range and further improves the activity; compared with a traditional fluoride brazing flux, the spreading area of ZN-15AL brazing filler metal on an aluminum alloy plate at 500 DEGC is improved by about 40%, and the spreading area of the ZN-15AL brazing filler metal on the aluminum alloy plate at 520 DEG C is improved by about 25%.

Description

technical field [0001] The invention relates to brazing technology, in particular to a composite brazing flux used in conjunction with zinc-aluminum low-temperature high-strength brazing filler metals to braze copper-aluminum dissimilar metals. Background technique [0002] The surface aluminum oxide film formed during the welding and heating process of aluminum alloy has high chemical stability and is difficult to remove, which seriously hinders the wetting and spreading of solder. The role of aluminum brazing flux is to melt before the solder during brazing, remove the oxide film on the surface of the aluminum alloy base metal, and form a layer of liquid film on the surface of the base metal to promote the wetting and spreading of the solder on the aluminum alloy surface to achieve Protection purposes. The traditionally used aluminum chloride flux has better film removal effect, but its residue after welding is easy to absorb moisture and has strong corrosiveness. Strict ...

Claims

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Application Information

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IPC IPC(8): B23K35/363
CPCB23K35/3605B23K35/362
Inventor 张青科龙伟民马力钟素娟朱坤裴夤崟孙华为丁天然薛行雁刘洁张冠星马佳
Owner ZHENGZHOU RES INST OF MECHANICAL ENG CO LTD
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