Hi

The ASME VIII, Div.1 design code, is closely connected to the materials and allowable stress values listed within ASME II, Part D, Ie. you can design a 316L cylindrical shell using the allowable stress values listed in ASME II, Part D, Table 1A.

In Europe the PED is mandatory and for that matter in some (or many) cases, harmonised European materials are used instead of ASME/ASTM materials. Ie. 1.4404 will "replace" 316L, as these materials are considered "equivalent".

The PED accepts the ASME VIII, Div.1. design code, but is it acceptable/reasonable to use European materials, ie. 1.4404, within the ASME design code, using allowable stress values based upon yield- and tensile strength values from the European harmonised standards?

As far I know, the ASME/ASTM allowable stress values in ASME II, Part D, are based upon the 0.2% yield strength and trend curves. The European materials are based upon other testing methods (ie. EN 10002). For austenitic materials the 1.0% yield strength value are generally used when deriving allowable stress values in design codes as AD-Merkblatt, EN 13445 and so on.

But when it comes to the ASME VIII, Div. 1, which strength values should I use?

Comparing 316L and 1.4404 allowable stress values based upon Mandatory Appendix 1 within ASME II, Part D, you will actually find that 1.4404 gets a higher allowable stress value than 316L, when using the 1.0% yield strength value for 1.4404.

I know that some NB's in Europe do accept this in PED cases, but in my opinion one should use the 316L values instead, as it is stated in the notes following Table Y-1 within ASME II, Part D: "The tabulated values of yield strength are those which the Committee believes are suitable for use in design calculations.". From that statement one could reason, that it is not appropiate to use a higher yield strength value. It is the same with the tensile strength (Table U).

This is not a question just relating to 1.4404 vs. 316L, but rather a question whether or not it is reasonable to use European material strength values when deriving allowable stress values for the ASME VIII, Div.1 design code and in connection with the PED (outside Europe I am quite sure it should be the 316L stress values that should be used).

Your opinions on this subject, please.

Best regards
Lars

PS: I have loooked, but could not find anyting on this subject that answered my questions.

Hi,
Vendors very often use ASME code as a design rules to comply with PED using ASME materials. Among many other things, which you need to fulfill req. of PED, you need to get for ASME materials, Particular Material Appraisal issued by manufacturer and approved by Notified Body (NoBo).
There are also often used EN materials and ASME code. In this case you will need to get acceptance from NoBo of defining allowable stresses acc. to App. 1 of ASME sec. II part D, where one of the factors is based on tensile strength at design temperature, which you do not have for EN materials.

regards,
malyl.

Malyl

Thanks for the answer.

I am aware of PMa's and so on, when dealing with ASME/ASTM materials and the PED.

My questions/discussion above are related to European materials and the ASME Design Code.

I can, of course, ask various NB's, but also as stated in my post, many NB's already accept the use EN materials in the ASME code, even though that these materials not are listed in ASME II and that you in some cases (especially for austenitic materials) do have a somewhat higher allowable stress value, than the equivalent ASME/ASTM material listed in ASME II.

Is is reasonable to use a design code in that way?

Best regards,
Lars

HI,
In my opinion, as long as you will define allowable stresses strictly in accordance with mentioned before App. 1. and follow all other code and PED requirements, I see no problems.

regards,
malyl.