Re: [MW:15145] Problem about Positive material Identification (PMI)

Check with another PMI equipment preferably using XRF equipment.

On Tue, 28 Aug 2012 13:55:05 +0530
mohamed jubair <kmd.jubair@gmail.com> wrote:
> Dear all,****
>
> ** **
>
> In our boiler one major problem occurred in Positive
>Material
> Identification(PMI) test [Spectrum test]. ****
>
> ** **
>
> Description****
>
> Reheater finishing outlet(RHFO) coil****
>
> Material****
>
> T91****
>
> Size****
>
> ø 63 x 4****
>
> Process****
>
> GTAW only****
>
>Filler wire****
>
> ER 90S B9****
>
>Filler wire Manufacturer****
>
> D & H Secheron****
>
> Preheating °C****
>
> 185****
>
> Rate of Heating °C****
>
> 100/hr****
>
> Interpass temp °C****
>
> 190****
>
> Post heating °C****
>
> 100****
>
> PWHT °C****
>
> 750****
>
> Soaking Time****
>
> 90 minutes****
>
> ****
>
> Around 800 joints welded in the above approved procedure
>only. Filler wire,
> header stub, RHFO coil, weld metal undergone PMI test
>separately and all
> show positive material results as T91 except weld metal.
>Weld metal shows
> the Chromium content only as (4-7%){Reqd is 8-10.5%}.
> We can't find how
> it happened? Our Chinese consultant told to cut and
>reweld all the joints.
> But our contractor argued that we followed approved
>procedure and used
> approved vendor's consumable only. Please give a
>solution. Here I have
> attached one preheating cum PWHT chart of RHFO
>joints(for 11 joints,5
> thermocouples,1 recorder).All 800 joints are not checked
>yet. Only 40
> joints checked and all 40 weld metals shown low Cr
>Content.**
>
>
> Please go through the below readings of one RHFO
>joint.****
>
> *Description*
>
> *Filler wire*
>
> *Header stub*
>
> *Weld metal*
>
> *RHFO coil*
>
> Alloy****
>
> T91****
>
> T91****
>
> A-2****
>
> T91****
>
> Cr****
>
> 8.94****
>
> 8.34****
>
> 5.19****
>
> 8.68****
>
> Mo****
>
> 0.96****
>
> 0.90****
>
> 0.93****
>
> 0.92****
>
> V****
>
> 0.17****
>
> 0.17****
>
> 0.08****
>
> 0.19****
>
> Ti****
>
> 0.07****
>
> 0.10****
>
> 0.04****
>
> 0.03****
>
> Mn****
>
> 0.60****
>
> 0.40****
>
> 0.54****
>
> 0.63****
>
>Fe****
>
> 87.81****
>
> 88.11****
>
> 90.86****
>
> 87.61****
>
> Ni****
>
> 0.12****
>
> 0.33****
>
> 0.20****
>
> 0.38****
>
> Cu****
>
> 0.02****
>
> 0.16****
>
> 0.20****
>
> 0.16****
>
> Nb****
>
> 0.09****
>
> 0.08****
>
> 0.03****
>
> 0.04****
>
> W****
>
> 0.15****
>
> ****
>
> 0.00****
>
> ****
>
> ** **
> Waiting for your valuable suggestions.
>
> Thanks & Regards
> K Mohamed Jubair
>
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> The views expressed/exchnaged in this group are members
>personel views and meant for educational purposes only,
>Users must take their own decisions w.r.t. applicable
>code/standard/contract documents.
>
>

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The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.