Pitting Corrosion On Inconel Overlay
Pitting Corrosion On Inconel Overlay
(OP)
Gents, I want to ask about the cause of pitting corrosion test (G48). Our product is inconel manually overlaid on API X65QS. the specimen passed on the chemcial composition test as client specification (Fe is 8%, Cr is about 20% and Ni is about 59%). As our experience, these kind of result shows no issue for pitting corrosion although the Fe content is above 5%. The microstructure also doesn't shows any intermetallic phase.
Is there any other potentially cause of pitting corrosion than chemical composition for overlay products?
thx all.
Is there any other potentially cause of pitting corrosion than chemical composition for overlay products?
thx all.





RE: Pitting Corrosion On Inconel Overlay
RE: Pitting Corrosion On Inconel Overlay
RE: Pitting Corrosion On Inconel Overlay
You would be looking for:
1. inclusions (usually oxides or slag)
2. porosity (see above comment)
3. significant variations in staining indicating significant amounts of segregation, that is local variations in chemistry (perhaps due to non-uniform feed or dilution)
Was this done in two passes? If not then it is hard to believe that you don't have carbides and other secondary phases.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Pitting Corrosion On Inconel Overlay
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Pitting Corrosion On Inconel Overlay
Mo is about 8.13%. We do three passes actually. My first thought is the heat input and the interpass temperature is too high. But after refers to the chemical result, it shows nothing issue actually.
I think Ed was right, about local variations in chemistry. Due to manual overlay, it's difficult to reach uniform results.
Thx all for your great answers!
RE: Pitting Corrosion On Inconel Overlay