WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
(OP)
What are your thoughts on the required NDE for alloy weld overlay deposit in a pressure vessel.
Is it necessary to apply UT to check for dis-bonding (as is applied to clad plate) given that with weld overlaid plate fusion strength between the alloy material and the base carbon steel has to be proven in the PQR.
For fully automatic processes like electroslag welding we would not expect fusion problems as long as the correct procedure is followed?
The overlaid surface should of course be dye penetrant checked to ensure no flaws or cracks in the surface.
Thanks
Is it necessary to apply UT to check for dis-bonding (as is applied to clad plate) given that with weld overlaid plate fusion strength between the alloy material and the base carbon steel has to be proven in the PQR.
For fully automatic processes like electroslag welding we would not expect fusion problems as long as the correct procedure is followed?
The overlaid surface should of course be dye penetrant checked to ensure no flaws or cracks in the surface.
Thanks





RE: WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
We also clad with 2 layers minimum.
RE: WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
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RE: WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
Dear friend,
In a pressurevessel, the carbon backing material is to withstand the pressure, and the overlay material to counter the corrosive environment or to maintain meaterial purity etc., In either case the tests need to be conducted while qualifying is the chemical composition at the required depth to be equivalent to better than intended, and the shear test as enunciated in ASTM A 263, 264 for the overlay. The thickness of iverlay is not considered for the thickness calculation for holding the designed pressure.
When this basic requirement is understood, the tests particularly NDE desired are to see that ther are no through opening to enable the service fluid to reach the base metal. Any test to evaluate the porosity level and and its depth should be sufficient. Please remember that if the overlay is Austenitic SS the options reduces further as the weld overlay wil not respond well to ultrasonic testing.
Regards,
MRCN
RE: WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
RE: WELD OVERLAY DEPOSIT and SUBSEQUENT NDE
Liquid penetrant inspection is recommended to confirm freedom from cracking and excessive porosity.