Cladding vs Overlay for Sour Service

[nickypaliwal]

1)Do we need NACE compliance for carbon steel if cladded with 625 or 825 ?

2)and do we need NACE compliance for parent metal for weld overlay ?

3) I believe, we need compliance for weldoverlay and not cladding .. Why ?

Also for HDPE lining, why do we need NACE for base material ?

 

[OGMetEngr]

1) Yes (according to NACE MR0175). Also the weld/overlay HAZ must comply with the standard.

2) This is question 1 reworded. Still a yes.

The reason is in case the cladding or lining integrity is compromised, you don't want your base metal cracking.

 

[SJones]

1) It's not a strict 'Yes' - there is an out if the end user can 'document' the reliability of the overlay or cladding

2) See 1

3) Compliance = compliance for the overlay, cladding or substrate? The question is not clear.

HDPE liners can permeate acid gases and water vapour, thus the corrosion process can occur at the metallic pipe surface

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.

 

[nickypaliwal]

I am talking about parent metal.. Do we need HIC testing and NACE compliance ?

 

[OGMetEngr]

The short answer is yes, the parent material must be NACE compliant. The overlay HAZ, which is also within the parent material, must comply as well. As SJones pointed out, there is a clause that allows one to use their "documented" reliability of the overlay to use parent material that doesn't comply with the standard.

 

[KMur]

in this case, parent metal need to be SSC tested or SSC resistant quality plate is required, but HIC tested is not required.

 

[nickypaliwal]

@KMur: Do u mean that SSC s required and HIC is not required for both cladding and Weldoverly ?

Thanks..

 

[KMur]

Yes nickypaliwal.
SSC is required. HIC is not required.

 

[nickypaliwal]

Thanks for clearance.. Why is HIC not required ? Is HIC required for parent metal in case of Non-metallic coating also ??