Filler wire for Copper materail

[Devang Majithia]

Dear All,

We have a Floating Head Cover assembly in exchanger which is having a material composition as follows:

Copper  : 68.5%.

Al         : 4.0%

Si         : 13.5%

Mn       : 7.6%

Fe        : 2.1%

Ni         : 1.4%

Zn        : 1.8%

Presently cracks are observed from weld and parent metal. Kindly advise suitable filler wire for carrying out repair work. We have tried to carry out welding with ERNi1 and ERNiCu7, but both time we are not successful. Presently we are thinking that may be ERCuMnNiAl can be used. Kindly provide your valuable suggestions. 

Requesting to also provide necessary preheat and interpass temperature parameters with comments.

Regards,
Devang Majithia