Re: [MW:28390] evaluating of micro structure

Dear Ramin.

I don't know how to explain my query about establishing of a criteria to evaluate microstructure and also why you insist on any lab's result is reliable with regarding you have similar experiences about fake results and MTCs.

anyway  I don't know how a experienced   metallogheraphers can be distinguished from another one? and whereas I know distinction untempered bainite from tempered martensite is only possible by TEM and why you say it is not difficult.

Regards.

   

On Thu, Oct 4, 2018 at 1:42 PM Ramin Kondori <raminkondori@gmail.com> wrote:

I am not sure if I understood your point

If you can't rely on MTC or lab results then what is this all about....?

It seems to me that you are not correctly communicating your message...

Tempered Bainite/Martensite is not that difficult to distinguish for an experienced metallurgist and it is not necessary for your specification to tell you how to do that. Leave it to the lab metallurgist. Of course, you have to be specific in your order.

Ramin  Kondori

Sr. QA/QC & Welding Engineer

-----------------------------------------------------------

PG-Dip. in Welding Engineering (IWE  AT  0070)

BSc. in Civil Engineering (IUT)

BGAS Painting Inspector

ASNT Level I&II

                        

On Thu, Oct 4, 2018 at 9:20 AM Ali Asghari <asgharialigl@gmail.com> wrote:

Dear Ramin.

Thank you for responding.

But surely you confirm me, buying from stock material or even during fabrication you can not rely on interpretation of the lab or MTC.

Therefore there is need to review them or even prepared some sample test to increase confidency since the consequence of failure in sour service is high.

Now for evaluating of microstructure  like as other essential variables (such as impact/chemical/tensile) has to be a criteria that lab say it is completely tempered or not.

I am looking for that criteria which it contains some reference figures.

Regards.

On Wed, Oct 3, 2018 at 4:32 PM Ramin Kondori <raminkondori@gmail.com> wrote:

I'm afraid you are not clear enough...

If you want the "know-how" and are wondering how to determine the microstructure, that is a huge topic itself. Leave it to the laboratory. Just tell them that you need to know what is the microstructure and ask them to be specific about the Bainite (upper/lower Bainite, tempered or not etc.) and give you the percentages.

The fact is the susceptibility to HIC/SSC of the steel with a higher fraction of bainite increases significantly. Bainite is generally not desirable for sour service. In this category of steels, fully tempered martensite has the best sour service performance, followed by lower bainite. on the other hand, untempered martensite and upper bainite reduce SSC resistance significantly and shall be avoided in sour service applications but if you have nothing in your specification discussing the microstructure in detail, then there is nothing to be worried about.

Now, that said, if you give us more details along with the material MTC, test results and images, then we can help you much better.

Ramin  Kondori

Sr. QA/QC & Welding Engineer

-----------------------------------------------------------

PG-Dip. in Welding Engineering (IWE  AT  0070)

BSc. in Civil Engineering (IUT)

BGAS Painting Inspector

ASNT Level I&II

                        

On Wed, Oct 3, 2018 at 8:01 AM Ali Asghari <asgharialigl@gmail.com> wrote:

Dear Ramin.

My question isn't for a specific grade or component and it is related to the micro structure of body of base metal.

In some documents especially for sour service material specification said that, there isn't any untempered micro structure and I am  wondering to establish a criteria.

Regards.  

On Tue, Oct 2, 2018 at 5:18 PM Ramin Kondori <raminkondori@gmail.com> wrote:

What is your material spec...?

if you have the MTC please share it. it is important. 

If this is a weld metal issue please share your WPS, details of welding of Test Coupon and also other available  PQR test results (if available). everything you have...

Furthermore, share your metallographic evaluation photos (it should be of high quality).

Regards

Ramin  Kondori

Sr. QA/QC & Welding Engineer

-----------------------------------------------------------

PG-Dip. in Welding Engineering (IWE  AT  0070)

BSc. in Civil Engineering (IUT)

BGAS Painting Inspector

ASNT Level I&II

                        

On Tue, Oct 2, 2018 at 10:51 AM Ali Asghari <asgharialigl@gmail.com> wrote:

Dear Meisam.

I have forgotten to say that ASTM have some adjuncts such as '' Photographs for Rating Macroetched Steel(ADJE038101 (Plate I), ADJE038102 (Plate II), and ADJE038103 (Plate III).'' and similar like that to help us for interpretation.

Regards.

On Tue, Oct 2, 2018 at 9:52 AM meisam shokri arfaei <meisamshokri@gmail.com> wrote:

Dear Ali,

If you look for differences between primary and tempered martensite, it needs some deep knowledge and experience which some metallogheraphers have it. Also it needs a brief history of the sample, special sample preparation, special and precise etching and ... .

For more information about visual differences in microstructures you could go through ASM Metals handbook Vol. 9 - Metallography.

Regards

On Tue, Oct 2, 2018 at 8:23 AM slick ronz <vinopvarghese@gmail.com> wrote:

Dear Ali,

Can you be more specific about the Material grade you are looking for? If we consider a case of P4 material like WP11, the heat treatment required is Normalised and Tempered condition. Hence the MTC shall mention this requirement and no further evaluation is required for micro structure examination.

Hope it answered your question.

Thanks and Regards,

Vino Varghese

Qatar

On Sun, Sep 30, 2018, 09:14 Ali Asghari <asgharialigl@gmail.com> wrote:

Dear All.

Does anybody know how it is possible to evaluate the bainite or martensite of the base metal is tempered or not?

I want to know the method , frequency of testing, acceptance( such as figures) and any other issues that can say with confidently we have tempered micro structure or not?

as you know this is more crucial in sour service and is a requirement in our specification but doesn't mention detail of it.

Regards.

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