New MTR required?

[JasonLouie]

If a fabricator will hot form a head at 1650F (SA 516-70N), is a new MTR required? They are essentially re-normalizing the material. Is ASME VIII UG-93(b) applicable in this case?

If a certificate of compliance is issued, do they need to issue support documents (i.e. tensiles, impact tests, etc) or will they just submit a signed document?

Thanks!

 

[rustbuster]

Typically a partial data report is required I believe.

 

[metengr]

Please read UG-85 in Section VIII, Div 1.

 

[JasonLouie]

Thank you very much rustbuster and metengr for your responses.

Sorry, got my details wrong - the head is cold formed then re-normalized at 1650F.

metengr, UG-85 takes me back to UG-93(b) where it states that a supplementary MTR or a certificate of compliance is required. The AI "shall determine that they represent the material and meet the requirements of the material specification". My interpretation of this is that the documentation needs new tensile test and charpy test results to prove that the material properties still meet the requirements of 516-70N. Is this correct? We have received a certificate of compliance with no mechanical testing to back their claims.

 

[metengr]

My interpretation of this is that the documentation needs new tensile test and charpy test results to prove that the material properties still meet the requirements of 516-70N. Is this correct?

Yes.

 

[JoeTank]

Metengr,
Seldom would I question your answers, but this one gives me pause. In 30+ years I have never seen a new set of physical tests performed after normalizing a cold formed head. Is that explicitly stated somewhere in ASME VIII or is it the result of a trail of ASME paragraphs? This is not a challenge. If I need to correct my thinking I will do so.

Joe Tank

 

[metengr]

JoeTank;
It is great to question responses on this site because I nor anybody else have all of the answers, and in some cases interpreting the OP can be difficult.

First read UCS-85. The issue of Certificates of Conformance and reheat treatment has been one that I struggled with in the Code, and still do. In my opinion, reheat treatment should require a supplementary MTR because of assurance in establishing the required minimum mechanical properties of the plate. Some parties and AI's have accepted C of C, but as an Owner, I require tests for reheat treatment to assure minimum mechanicals are met.

 

[metengr]

JoeTank;
One item that does confuse people is a thermal treatment after forming. There is stress relief treatment which is below the lower critical transformation to remove the effects of cold work, and then you have reheat treatment - normalizing, normalize and temper and quench and temper to alter the effects of cold work and to remove the weld heat affected zone. The subcritical thermal treatment (stress relief) does not require any supplemental testing, you heat, monitor with TC's and cool.

Reheat treatment on the other hand will alter mechanical properties because you may not duplicate what was done according to the original MTR. Did this answer your question or alter your thinking?