Chemical analysis mentioning in WPS and PQR for hard facing overlay weld

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sathis...@gmail.com

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Mar 29, 2020, 8:06:15 AM3/29/20
to Materials & Welding
Dear Experts
Process:PTAW
MATERIAL GRADE:P.NO.1,8,5A,15E
Hard facing overlay welding
4 to 5mm welded and machined to 1.6mm. Found hardness and macro examination cleared

QW-216.4. It defines that chemical analysis nominally matching the weld deposit chemical analysis may be substituted to qualify the PQR. Can anyone explain this meaning?

Recently I have qualified hard facing weld overlay. In that during chemical analysis I have got C, Si, Mn, P, S, Cr, Mo, Ni, W, Fe and CO chemical elements. So actual attained chemical composition I have mentioned in PQR. During WPS preparation I have mentioned only nominal chemical elements i.e., Co, Cr, W, C only as explained in the QW-216.4.

But my TPI agency is opposing my prepared WPS. That they are telling to put all the elements in WPS. I have argued them that this is the nominal chemical elements important for hard facing. However I have tested in 1.6mm after weld to the machined surface. So Fe comes to 5 to 10%. However I have cleared the Macro and hardness examination.

Also I have previous done the same paremeter and same has been accepted by same TPI. This same also shown but they are rejecting this was signed on 2016 and based on client request only we accepted this.

Note: I have explained them this elements Cr,Co & W -All are very important in HF overlay welding. Cr- Increase the Corrosion resistance.Carbide formation of Cr,Co & W - It will increase the hardness value and wear resistance.

But although they are rejecting my request. Please clarify

George Dilintas

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Mar 30, 2020, 1:15:22 AM3/30/20
to material...@googlegroups.com
Your TPI is right, read the Code:
(d) When a chemical composition is specified in the
WPS, chemical analysis specimens shall be removed at locations
specified in Figure QW-462.5(b) or Figure
QW-462.5(e). The chemical analysis shall be performed
in accordance with Figure QW-462.5(a) and shall be within
the range specified in the WPS. This chemical analysis
is not required when a chemical composition is not specified
on the WPS.
If you specify the chemical analysis in the WPS then you have to confirm by testing that you achieved what you have specified in the WPS.
So read the Code carefully otherwise you shoot on your own legs

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Dr. Georgios Dilintas,
Dipl. Ing. In Aeronautic and Space Engineering
Ph.D in Mechanics of Solids - Computational Mechanics
A.I.S, A.N.I, IRCA Lead Auditor
Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis

Kannayeram Gnanapandithan

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Mar 30, 2020, 1:15:28 AM3/30/20
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Chemical analysis is not mandatory in PQR unless it is mentioned in WPS before PQR Qualification. Whatever the elements mentioned in WPS, it should be done in PQR. Ref QW 216. 

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