welding of monel

By - Date 10-20-2004 14:22

Gentlemen,
I have just learned that we will be building a large, complex (i.e. some tight tolerances requiring machining) seawater service structure out of Monel. I was told that thicknesses will be up to 50mm (2"). I have not seen any drawings as of yet and this is all the information that I currently have. To compound matters, I have very little experience with monel.
Does anybody have any experience with this material and advice that you can pass on? Any information would be of use (e.g. consumables, processes, techniques, shrinkage, difficulties to be expected, etc).
Thank you in advance.
Mankenberg

By pipewelder_1999 (****)

Date 10-20-2004 18:20

We did quite a bit of this when I was in the Navy. It does not wet out like carbon or stailess or even as good as inconel. The puddle is a little sluggish. In my oppinion if you do not keep the arc ant or very near the leading edge of the puddle you can easily get areas of incomplete fusion.

The base metal needs to be VERY clean. Sulfur bearing compounds are bad.

The composition is around 60 40 Nickel to Copper so this will weld like many of the other high nickel alloys. The slag from the SMAW electrodes I used was VERY tough to remove but I'm sure there are some better ones than the ENiCU-7's we had.

Excessive heat input causes surface oxidation that seems to form a thin scale if GTAW welding that is a pain to work around.

Hopefully someone with some more recent experience will offer some advice.

Have a nice day

Gerald Austin