Cu-Ni CRO on CS plate

Date 06-01-2009 06:16

I have to qualify a Procedure for Cu-Ni Corrosion Resistant Overlay welding on CS (A516 Gr70) plate. I used ER CuNi-7 for barrier layer(Ist layer) and ER CuNi 90/10 for rest. But I found cracks while doing the barrier layer welding. Previously made Test coupon also failed in Bend test. It shows cracks in the entire length of welding from the barrier layer itself. Any suggestions? or What may be the reason? I checked the filler wire for Iron content <1.0%

By Steve.E (**)

Date 06-01-2009 09:18

Monel overlay...... AAAArrrrr I hate that stuff ...Im assuming your using GMAW , from memory you should be putting down a layer of CuNi-10 first. Better still a layer of straight Ni.
Good luck thats one of the most crack happy alloys Ive had the pleasure to work with . Low dilution is the key.

By Steve.E (**)

Date 06-11-2009 09:55

Would really like to hear some other comments or recommendations on this one. I'm not that young that I know everything. :)

By MMyers

Date 06-11-2009 12:31

Steve's right. You're pulling too much iron from the base into the buffer layer which is causing the cracking. Lowering your dilution would help this. Special Metals has some info on the topic: http://www.specialmetalswelding.com/publica/joining.pdf (page 16).