UT Acceptance Criteria for Corrosion Resistant Weld Overlay

[normankiddie]

I would like to find acceptance criteria for a ASME VIII vessel that has been overlaid with corrosion resistant material. We are debating the acceptance criteria on disbonding, any ideas?

 

[metengr]

I believe that the Code does not provide specific guidance for corrosion resistant weld metal overlay acceptance criteria (in terms of bonding, etc). This should have been specified in the contract document. There is guidance for performing ultrasonic testing of weld cladding, in Section V. However, the acceptance criteria is specified by the owner of the vessel.

 

[Goahead]

In order to establish acceptance criteria for UT you probably need to qualify the process by bend testing.
Such a qualified panel may then be used as reference.

http://www.welding-advisers.com/

 

[metengr]

Goahead;
Qualification of the corrosion resistant weld overlay (CRO) procedure is required in accordance with ASME Section IX, Table QW-453. The issue I believe is actual examination in production. In this case you have several important variables - CRO thickness, chemical composition to assure no effect from dilution and bond integrity. This should have been listed in the contract documents or engineering specification prior to fabrication.

Regarding acceptance criteria for bond integrity, you can develop a grid system and scan using an L-wave to determine % bond within a designed area. On first go around I would insist on greater than 98% bond integrity with isolated areas containing lack of bond limited to a certain size (not to exceed). Regions containing lack of bond that are spaced below a minimum distance are unacceptable.

 

[SJones]

Try ASTM A578. We use acceptance level S6 if it's any help to you (that's for both clad and overlay).

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/