Copper-Phosphorous Brazing Alloys

Copper-Phosphorus alloys have outstanding brazing properties and wide capabilities. Phosphorus will alloy readily with copper. Phosphorus is a reducing agent for copper and also deoxidizes silver. These brazing alloys of copper-phosphorus and silver-copper-phosphorus are self-fluxing on pure copper.

The reduction of phosphorus and additions of silver have a profound effect upon the fluidity of brazing alloys. The alloys of higher phosphorus content are extremely fluid, while the lower phosphorus, high silver alloy has a broad plastic range. Even small adjustments in alloy percentages have a marked effect on brazing alloy fluidity.

These brazing alloys are primarily used for joining copper and copper alloys and copper-phosphorus can be used for all brazing processes.

CEAC Alloy	Material Description	Industrial Specifications	Solidus Deg.C Liquidus Deg. F
LCU-1	Particularly useful for resistance brazing. It is more ductile than the other alloys in this series. It is also less fluid at the brazing temperature.	AWS BCup 1	1310 1965
LCU-2	LCU-2 and LCU-4 are extremely fluid at brazing temperatures and will penetrate long joints or those with little clearance. Joints exhibit high tensile, sheer strength, and excellent electrical conductivity.	AWS BCup 2	1310 1460
LCU-2a	A proprietary fluid brazing alloy that wets metals very well. It is more economical than LCU-4.
LCU-3	LCU-3 & LCU-5 are to be used where very close tolerances cannot be held. These alloys are characterized by a wide paste range.	AWS BCup 3	1190 1495
LCU-4	LCU-2 and LCU-4 are extremely fluid at brazing temperatures and will penetrate long joints or those with little clearance. Joints exhibit high tensile, sheer strength, and excellent electrical conductivity.	AWS BCup 4	1190 1325
LCU-5	LCU-3 & LCU-5 are to be used where very close tolerances cannot be held. These alloys are characterized by a wide paste range.	AWS BCup 5	1190 1475
LCU-6	Combines some of the properties of LCU-2 & LCU-3. It has the ability to fill gaps at the low end of its brazing range and is very fluid at the high end. It is ideal for jobs where brazing temperature is a critical factor.	AWS BCup 6	1190 1450
LCU-7	More fluid than LCU-3 and has a lower liquidus temperature. It is used for brazing heat exchangers and tubing joints.	AWS BCup 7	1190 1420