Inco 625 overlay on pipe(wall thickness 25.4 mm)

[gafoorkti]

Hi Gents,

I have a question regarding Inconel 625 weld overlay(3mm) inside pipe (wall thickness 25.4 mm). Please tell me with code refernce "if stress relief after weld overlay is required or not".

Construction code: ASME B31.3 and welding as per ASME IX.

Regards

 

[EdStainless]

It would depend on the pipe material.

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Plymouth Tube

 

[gafoorkti]

Pipe material is API 5L Gr.B/ASTM A106 Gr. B dual certified.

 

[stanweld]

No. Please review 331.1.3. However, the buttwelds joining the weld overlayed pipe are subject to PWHT.

 

[gafoorkti]

Para or table??

I can't interpret. Please elaborate.

"Base on the code, PWHT is required for P no. 1 material when wall thickness more than 19mm". In this case why it is not applicable?

Regards

 

[metengr]

There is no specific guidance for exemption to PWHT for CRO - corrosion resistance overlays in B31.3 under nominal governing thickness. Thus, service conditions need to be considered and the effect of residual stress from a weld overlay.

Check for any interpretations issued by B31.3 regarding the application of CRO's and exemption to PWHT.

 

[SJones]

Is ISO 15156-3 also applicable to the work in question?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[gafoorkti]

yes, service is sour and NACE-MR-0175 is applicable.

 

[SJones]

If the hardness tests on the substrate were within the limits prescribed by ISO 15156-2, then no further heat treatment would be necessary. Reference may be made to inquiry #2004-11. It can only be assumed, from the response given by the Maintenance Panel, that they consider overlay welding to have produced a compliant heat treatment condition of the substrate.

As has been pointed out, the butt welds will be subject to PWHT which may affect the corrosion resistance of the 625 and, if you are the end user, you may wish to consider some form of supplementary testing of the heat treated material to confirm acceptable properties.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[bernoullies123]

Just to re-confirm the responses already noted in regards to butt-weld joining...

B31.3 clad welding 323.4.3 refers you to BPV UCL-34 PWHT. BPV first starts off with a 'CAUTION' about possibly affecting the corrosion properties via heat treatment, then goes onto to say that yes, heat treatment shall be done per the base metal thickness.