Dissimilar welds involving Copper Nickel 70/30

[Seeker88]

Hi folks,

I am about to start manufacturing a pressure vessel in Copper Nickel 70/30 material. We have lots of existing qualifications for the 70/30 material but the end user now wants us to weld test pieces and gain qualification for 4mm fillet welds joining the following;

P1 material to the 70/30 cupro nickel.
Monel 400 to the 70/30 material.

Couls I please ask if it is first of all possible to weld the two disimmilar materials to the 70/30 material? Secondly, could someone please point me to a good source of information so that I can research and set up the weld test pieces. The design code is PD5500 but the qualifications will be performed to EN 15614 etc. My particular concers are weldability, guidance, selection of consumables and avoiding any PWHT after welding.

Thank you in advance

Brian

 

[EdStainless]

The Monel 400 to 70/30 should be straight forward.
The P1 will likely require buttering with a pure Ni, then using a Ni-Cu filler.
With the huge difference in melting points this joint would usually be brazed.

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

My suggestion is to review the attached literature first;

https://www.copper.org/applications...oining_welding_cutting_lining.html#dissimilar

and

http://www.specialmetals.com/assets/smc/documents/smw/we187.pdf

Next, your weld coupons should be groove welds with the dissimilar metal weld joint combinations per the code of construction. The construction code should provide guidance related to preheat and PWHT for the metals above, individually.