acceptance standards for pittings for SA 516 GR 70 Plates

[asad azmi]

Dear All,

 

Greetings.

 

what is the acceptance standard for pittings on SA 516 GR 70 Plate.

 

I mean what is the depth and diameter allowed.

 

Thanks and Regards

 

Asad Azmi

[Jorge Mejía Lema]

Dear Asad Azmi: your question is a general one. Would you like to define the material application and the phisical conditions which the material have to be used. For example: for API 653 "Tank Inspection, Repair, Alteration and Reconstruction" there is an evaluation of Corrosion Areas, see Numeral 4.3 Tank Shell Evaluation. If you will use the plate por Pressure Vessel you have to do some calculation base in service condition ( pressure, temperature and dimensions). There is a technic call "Fitness for Service"

Regards

jml

2011/4/25 asad azmi <azmias...@gmail.com>

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[Kathalingam Babu]

Hi Azad,

 

You can consider the CA, as allowable depth of pitting allowed for the respective grade.

 

What is the construction code ?

 

Thanks & Regards,

 

K. Babu

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[asad azmi]

Dear mr. Babu,

 

construction code is ASME SEC VIII DIV 1.

 

Pittings were observed  on the plates during material receiving inspection.

 

pls inform me what is CA.

 

thanks and regards

[Kathalingam Babu]

Hi Azmi,

 

CA-Corrosion Allowance

 

You may refer the material spec. to get the CA.

[Dindo]

Hi Azmi

 

If it is for new construction, then you can check the minimum thickness, If it doesn't meet your PO or thickness requirement then you can reject the plates, the supplier should have fix the pitting on their side and done all NDE required.

 

Ricardo

[asad azmi]

Dear Mr Ricardo,

 

is it acceptable if plate thickness is  within acceptable limit and piting can be left as it is.

 

is there any surface conditionong/smoothenening is required or not.

 

 

 

pls suggest and give code reference if possible.

 

thanks and regards

[sunil javed]

There is a tolerance for the thickness for the recied materials in Sec VIII div 1, I think that is 20% of PO thickness. Please verify, I donlt have the code with me now to specify the paragraph.

 

I think, we can accept the plate if the remaining thickness after removing the pitting area, by gtinding and actual thickness check, is meeting the design thickness including CA, we shall not remove the CA from the acailable thickness as this is the new project material. we shall not go upto the CA (normally this will be 2 to 3 mm).

 

Javed

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[Ahmad, Aftab]

I believe the depth of the pitting should not exceed 10% of the nominal wall thickness viz the manufacturing tolerance.

 

Best Wishes

Aftab Ahmad

 

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