Weld repair of Super Duplex casting
Weld repair of Super Duplex casting
(OP)
We are facing problem in weld repair of Super duplex grade 5A Casting to radiographic quality. Can anyone suggest tips on what care need to be taken especially in gauging and excavating the casting and also subsequent solution annealing of castings





RE: Weld repair of Super Duplex casting
use matching filler (as close as possible)
keep interpass temp low
solution anneal per spec, rapid cooling is critical.
Have the castings already been annealed?
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Plymouth Tube
RE: Weld repair of Super Duplex casting
Do think it would be cool to know exactly which superduplex alloy is involved.
Whatever is "Grade 5" it does not refer to a specific alloy chemistry.
RE: Weld repair of Super Duplex casting
RE: Weld repair of Super Duplex casting
The casting is already solution annealed as the spec and is taken for Radiography where in the defects revealed and we are working to salvage the casting.
We have used this electrode and done weld repair in the past and no issue but facing problem in this instance and the casting weight is 1600 kgs.
While gouging for removing the defects, multiple cracks propogate.
RE: Weld repair of Super Duplex casting
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RE: Weld repair of Super Duplex casting
The heat from the arc may be causing enough embrittlement near the defects that you will only cause more cracking.
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Plymouth Tube
RE: Weld repair of Super Duplex casting
Be careful when quoting 'matching' filler metal for duplex SS, because the composition is typically overalloyed with nickel to produce the same ferrite/austenite ratio in the as-welded deposit. Follow the filler metal manufacturer's recommendations for that. Avesta will have lots of good info.
RE: Weld repair of Super Duplex casting
RE: Weld repair of Super Duplex casting
I don't advise that unless it comes with a qualified welding procedure.
RE: Weld repair of Super Duplex casting
RE: Weld repair of Super Duplex casting
It may be possible to cool 1600kg fast enough after PWHT - it all depends on section thickness, configuration of the piece being welded, and the size of the quench tank.
If your base material has been certified with impact testing, microstructure and ferrite volume, corrosion testing or is for NACE duty, take these into account before carrying out your weld PQR.
RE: Weld repair of Super Duplex casting
Per ASME Sect IX, any change in gas mixture makes a new PQR/WPS mandatory. I should have mentioned that.