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AWS A5.7 – ERCUNI (70/30)

Base materials

Particularly suitable for high stressed corrosion resistant weld surfacing on cast iron and on unalloyed and low- alloyed steel as well as seawater resistant CuZn alloys. Suitable for welding on CuNi.

Shielding gas

Argon, Helium or Argon/Helium-mixtures


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Typical Applications

Tube sheets Pickling hooks Impellers valve seats
Chemical plants Pulp mills


Limiting Chemical Composition
Copper* Balance
Aluminum 6.0- 8.50
Manganese 0.50 max
Silicon 0.10 max.
Others 0.50 max
Mechanical Properties
Tensile Strength ksi 68 (469 MPa)
Yield Strength ksi 28 (193 MPa)
Elongation % in 2″ (51 mm) 47
Reduction of Area % BHN (3000kg.) 53
1/4″ (6.4 mm) deposit 125


AWS A5.7 Class ER CuAl-A1 ASME SFA 5.7 Class ER CuAl-A1
*Hardness will vary depending on quality of the weld and experience and knowhow of the welder.

Document Download

AMPCO-TRODE® 521 Technical Data Sheet