Rated MDMT 1

[AB53Mech]

Hello Respected Members ,
I am trying to run calculation in COMPRESS , for NPS18 Sch120 - SA-106 C smls pipe as cylinder and 2:1Ellip Head 1.25'' Thk SA-516 Gr.70 . Used MDMT is -20deg.F. Design Pressure 2500psi @350degF .
So in result : In Deficiencies report, it gives me that one note : '' for Cylinder Pipe The Rated MDMT of 4.65 deg F is warmer than the design MDMT of -20 deg.F'' & for the Head rated MDMT 0.95 deg F warmer than -20deg.F ''
My request to you , can you please kindly guide me how to remove this deficiencies ? do I need to go with Impact testing check option on it ? Additionally do I need to put full complete vessel for PWHT or just Head and Shell only? I guess as per SecVIII div.1 for SA-516 Gr70 thickness above 1.5'' Normalize is mandatory . but Is it mandatory to put complete vessel as PWHT option on it too?
And after running all different calculation , If I will put / check mark all these 3 option Impact tested , Material Normalize , and PWHT performed , than only I can be able to get report without deficiencies. Do I really need to put all these 3 condition on complete Vessel ?

Thank you .
- AB53Mech.

 

[fegenbush]

Change your material specification to the appropriate grade of SA-333. Grade 6 is close, but the allowable stresses are different.

 

[mechyp]

AB53Mech
I assume that mention MDMT of Pipe and Dished head is reduced MDMT.

For Dish you need to use SA516 GR70 Plate in Normalized condition.It is falling in Curve D of UCS-66 and allow MDMT up to -21°F for Nominal Thickness 1.25". same will exempt form impact test.
For Pipe you need to go for Impact testing because if you use pipe falling in Curve B that allow MDMT up to 10°F only.

Correct me if I wrong.

Regards
mechyp

 

[SnTMan]

AB53Mech, I suggest you start by closely studying relevant portions of Part UCS-66 and its references. Then you will know what to tell your software.

Regards,

Mike

 

[marty007]

Remember, the software is only a tool. Ultimately the manufacturer is responsible for the safety of the vessel, and compliance with any required laws and regulations. The questions you are asking imply that you are using the software without an adequate understanding of the ASME VIII-1 code. Are you comfortable knowing that if something goes wrong with the vessel and kills someone, it will be your responsibility (assuming you are a manufacturer)?

1) Learn the code.
2) Understand how the software is applying the code rules.
3) If the first two points do not result in an answer to your question, come and ask again.

 

[AB53Mech]

- Thank you everyone for helpful guide lines on it .

yes , I agree I really need to do some detail close CODE studies on it . Infect in general I am trying to read and study lot of times CODE with the help of CODE books , different books, online forums, I guess these are the way to get more involve in to the code . As much as I do discussion with experience people I can be more clear .

Regards ,
- AB