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Description and Application

A silicon bronze welding alloy (UNS C65600) for the inert gas welding of copper-silicon, copper zinc, copper to copper and also mild steel. Used extensively in the welding of galvanized steel. The silicon content of 2.8-4%, increases tensile strength, hardness, and work hardening rates.

Silicon bronze also provides good corrosion resistance and has good weldability.

Silicon bronze is hot short and extreme care must be exercised to avoid overheating the joint which tends to cause cracking.


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Welding Procedure

With gas metal-arc welding, the weld metal should be deposited in stringer beads, maintaining a small molten pool to avoid overheating the hot short silicon bronze base metal. Use argon gas for shielding and relatively high welding travel speeds.

With the gas-tungsten arc welding process, welding is accomplished with DCEN current and argon or helium gas shielding. ACHF with argon gas shielding may be used to take advantage of the arc cleaning action.


Preheat slightly to remove moisture.
Interpass temperature should not exceed 150°F (66°C).

% (filler metal)
Copper Balance
Silicon 2.8 – 4.0
Zinc 1.0 max.
Tin 1.0 max.
Manganese 1.5 max.
Iron 0.50 max.
Aluminum 0.01 max.
Lead 0.02 max.
Others 0.50 max.
Mechanical Properties
(Nominal all-weld metal values)
Tensile Strength ksi 50 (350 MPa)
Elongation, % in 2″ (51 mm) 40
BHN (500 kg) 1/4″ deposit 80


AWS A5.7 Class ER CuSi-A

Document Download

SIL-TRODE® Technical Data Sheet