SA-285 Grade C Weldability

[jgibbs22]

Hey Everyone:

I am working on a repair specification for a vessel from the 50's made of SA-285 Grade C (Firebox). I have to put some overlay patches on some corroded areas, and was hoping to get some opinions on what material to use. Will new SA-285 Grade C be ok? Can I still ignore the PWHT since my thickness is only 3/8", or because the original material was Firebox should I perform PWHT as a precaution?

Any recommendations would be appreciated. Thanks!

Jason

 

[metengr]

First, is this a pressure vessel or atmospheric storage tank?
Second, what is the code of construction - API or ASME Section VIII, Div 1?
Third, ASME SA-285 Grade C material would be the proper choice for weld repairs. A flush path plate may be required versus a simple patch plate.
Fourth, PWHT will not be required based on the 3/8" base metal thickness.
Fifth, you should qualify a welding procedure specification for the repairs.

 

[jgibbs22]

Metengr:

Thank you for the reply! It is a pressure vessel, about 20 psig, built to Div. 1

I was just concerned if the chemical composition changes from the current Code to the Code of Construction was different enough to warrant a different material, and if it mattered that it was Firebox and not Flange. I will comfirm the flush vs. Patch, I have multiple areas to do, so have not given specific direction on each area just yet. And I will definitely qualify a procedure, is there a common method and filler material used for weld overlay when just cleaning up corrosion? I think we are doing SMAW.

Jaosn

 

[metengr]

No, the current material specification will be acceptable for flush patch weld repairs, because if you are performing weld repairs to the National Board Inspection Code scab plates (external patch plates) are not permitted. Ok, last but very important question, do you have a current National Board R- Certificate of Authorization to perform said weld repairs?

 

[weldstan]

Firebox quality simply meant that it was fully silicon deoxidized. The material is readily weldable. No PWHT is required unless it was originally required for service.