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PMI to define chemistry composition weld joint after welding!

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WinWin2022

Mechanical
Nov 17, 2022
3
VN
Dear Sir/Madam!
Thank you for listening my question!
In my shop floor have conducted 1 weld joint as:
Pipe (A672-C60 CL12) + Elbow (A234-WPBW)
Filer metal: ER70S-6 2.4
We conducted PMI for this weld, result as picture
Because Cacbon steel, so when PMI is appeared Fe & Mn composition
I want to know Accept Criteria PMI for this weld (How much percent Mn be accepted?)
As result picture bellow be accepted or not?
At Pipe
Picture1_mniwiy.png

At weld
Picture2_dma908.png

At Elbow
Picture3_wcgshu.png
 
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You PMI equipment will not provide truly accurate quantitative results. Why are you using it for such a weld? In all my decades of experience with PMI of ASME Codes related carbon steel systems, I have never seen such a requirement. We did use portable spectrographic equipment to asssure appropriate Ni content in weld metal per client on a North Sea gas processing plant.

 
Reference ASME Section II, Part C, SFA-5.18

Table 1 Manganese requirement range for ER70S-6 = 1.40 - 1.85 weight percent.

Also reference ASME Section IX, Table QW-442. ER70S-6 is A-No. 1 weld metal. Maximum Allowable Manganese = 1.60 weight percent.

Manganese percentage is acceptable, per ASME Section IX Specifications.

As weldstan stated, this is an unusual requirement for Carbon Steel. Typically, PMI is not required for these materials.

I would recommend lightly grinding another few small areas around the same weld and see what the results are.

 
One other thing to consider. Industry standard for PMI results is usually accepted for +/- 10%.

You will have to check your customer specifications or your own quality standards to see if this is acceptable.

1.4 * 10% = 0.14 - 1.4 = 1.26%



The devil is in the details; she also wears prada.
 
Do you know what reference standards were used?
Was this done in high precision mode?
Did you also check both of the base materials to see if you get results that match those MTRs?
Do you have heat lot traceability on the filler metal?

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P.E. Metallurgy, consulting work welcomed
 
Unless the project also includes some high alloy (steels or SS) welds I agree with D Sen, no point.

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P.E. Metallurgy, consulting work welcomed
 
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