Inconel inlay per API 17D

[salmon2]

We need to refurbish some API flanges per API 17D. This standard states all flange ring grooves shall be inconel 625 inlayed for subsea application. But I didn't find anywhere specifying thickness of inconel inlay. Does it specify thickness at all? NORSOK M506 mentioned CRA overlay shall be 3mm (0.125'') thick and I read somewhere that HAZ shall be another 3mm...

Another following question is if I can use any PMI NDE test methods to verify this inconel inlay? I am wondering if a PMI has a min thickness to give any reliable reading. For example, XRF is sending x-ray to penetrate the surface and I assume it shall have a min thickness for the surface overlay. And any specific PMI methods or equipments to do this?

Thanks a lot.

 

[metengr]

salmon2;
Why not just machine the original inlay to removal, chemical etch to ensure complete removal of the original inlay and re-deposit using Inconel? This way you have a starting reference point for refurbishment, where you remove whatever remaining corrosion resistant inlay thickness is left and you start with a new inlay where you can control the depth to 1/8" deposit thickness or other thickness requirement. I would not try to establish remaining inlay thickness or condition because you will run into dilution problems. Do the refurbishment correctly.

 

[ak762]

metengr[/b]] I would not try to establish remaining inlay thickness or condition because you will run into dilution problems. Do the refurbishment correctly.

Could you give some tips in case with manufacturing new part.
After final machining cladded faces with NDT you are identifying places with porosity with thin layer in compare whole thikness of inlay. Obviously material have to be extract up to solid inconel. Question is: have to be cut out whole inlayed material or there are solutions to repare particular places?

 

[metengr]

If manufacturing a new part or component you have a reference point for depositing an inlay or interface layer (buffer) + corrosion resistant inlay. For an existing inlay I have dealt with refurbishment in the field and in the shop. Questions were always what is the remaining thickness of the inlay, what is the condition of the substrate beneath the inlay, etc. ?
Most times it boiled down to machining or removing what was left, verify the condition of the substrate (make any repairs if necessary) and re-deposited the new inlay to required specifications. Repairs if required to a new inlay are better controlled because you know what you have deposited in thickness. Never had a problem during refurbishment or in service performance.

 

[jbeckhou]

Looking thru Spec 17D, table 901.5 "rough machining detail for corrosion resistant API ring groove" will provide dims. To check the thickness of the weld, UT per API-6A instructions. I would recommend hardness testing the flange prior to welding. The WPS-PQR shall meet API-6A/NACE guidelines; see section 6 of API-6A for more information.

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