ASME VIII-1 MDMT Calculation for 1.25Cr-0.5Mo materials

[FPPE]

Hi,

Could you explain if MDMT calculation is necessary for 1.25Cr-0.5Mo materials under ASME VIII-1 and PED and if yes, which are the steps?
Thank you in advance

 

[david339933]

1.) Maybe.
2.) explain the steps...no. you need help.

 

[SnTMan]

For Sec. VIII, Div. 1: 1.25 Cr-0.5 Mo materials fall under Part UCS. UCS 66 rules apply.

For PED, no idea.

Regards

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[IdanPV]

Materials for use in PED pressure vessels shall met the requirements of ANNEX I, Paragraph 4.
See also Guideline G-17.

 

[FPPE]

Thanks Idan, I know that for PED if the minimum design metal temperature is equal, for example, at -12degC, we have to use material impact tested at that temperature or colder.
Now, since this ASME project falls under PED law and all 1.25Cr-0.5Mo materials used have been impact tested at required CET, is there an exemption from ASME impact testing requirements since the material actually has the impact tests?

 

[IdanPV]

ASME is your construction Code?

 

[FPPE]

Yes, but exchanger will be marked CE, not U

 

[IdanPV]

As far as I understand the situation, the requirements of your Constriction Code (ASME) shall be met as well.

 

[mk3223]

Now, since this ASME project falls under PED law and all 1.25Cr-0.5Mo materials used have been impact tested at required CET…

Here are two points,
1. IMO, a project design basis doc should be existed for the project which is to list all the applicable Code and Standards for the work, i.e. either ASME or PED, or both. Is it correct?

2. If both ASME and PED Codes are applicable, the project design basis may specify the stringent requirements of two Codes should normally be applied for the work, UNO.

 

[FPPE]

Thank you mk3223, I agree with you, especially on point 2.

I would like to know if there is even one sentence in the ASME code that does not make the design fall within the impact test conditions because the materials used are tested at the minimum temperature.
For example, by code the SA 350 Gr. LF2 CL1 is tested at -46 °C, so in UCS-66 this material is automatically exempted from impact test requirements if the minimum design temperature is -46 °C or higher.

Is there a similar clause (valid in general) in case the purchased material has the impact tests at the minimum design temperature?

 

[david339933]

Now that is a specific question that can be answered....see UCS-66(g) and general note C of Fig. UG-84.1.