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#17491 - 04/22/08 08:55 AM EN 13445 material database
VesEng1 Offline
Member

Registered: 04/22/08
Posts: 2
Loc: London, UK
Has anyone noticed that when using the european code the material data base in PV Elite 2008 has incorrect yield stress (@20degC) for the low temperature carbon steels e.g. P355NL1. I have used the code formula and yield stress reduction factors (interpolating) and they do not match the outputs given for materials in the data base.

If I have made an error I will put my hands up but, I have checked through this a couple of times and also looked at data base using PD5500 which to me looks a little more like the correct output. Maybe there has been an update for this version that I haven't received.

Can anyone shed any light on this subject?

Thanks

VesEng1

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#17533 - 04/23/08 06:50 AM Re: EN 13445 material database [Re: VesEng1]
Scott_Mayeux Offline

Member

Registered: 12/23/99
Posts: 347
Loc: Houston,TX,USA
Hi Ves,

We have in fact had some inquires about this particular material in the past. The material properties for the EN materials are standards purchased through BSI. It appears that there are some different flavors of this material in the database.

If you would care to work with us directly, we can show you how these stress values are developed.
_________________________
Scott Mayeux
CADWorx & Analysis Solutions
Intergraph Process, Power, & Marine

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#17593 - 04/25/08 12:49 AM Re: EN 13445 material database [Re: Scott_Mayeux]
VesEng1 Offline
Member

Registered: 04/22/08
Posts: 2
Loc: London, UK
Thanks for the response.

Sure no problem, I am keen to be in the know.

Just let me know how you would like me to deal direct with you then we can proceed.


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#17626 - 04/28/08 08:39 AM Re: EN 13445 material database [Re: VesEng1]
Scott_Mayeux Offline

Member

Registered: 12/23/99
Posts: 347
Loc: Houston,TX,USA
Ves,

You can send your calculation of the allowables to techsupport@coade.com and they will get routed to the right person.
_________________________
Scott Mayeux
CADWorx & Analysis Solutions
Intergraph Process, Power, & Marine

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#17801 - 05/06/08 02:02 PM Re: EN 13445 material database [Re: Scott_Mayeux]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
We have had this question a number of times. Let me explain where we get our material properties for P355NL1 1.0566 from. We get the values from BS EN 10028-3: 2003 which we purchase from the British Standard Institution. So, we can only use the information we are given from that specification. We use Table 6.1 from EN 13445 Part 3 in the determination of the design stress. The specification shows me that the design stress for P355NL1 are as follows: Rp0.2 is 355 MPa, and Rm is 490 MPa for plate <= 16 mm. Now this is important: There are no values for elevated temperature properties. Therefore properties are only given for 20OC, or room temperature. Now, I want you to look carefully at this table (click on the P355NL1.gif at end of the message):


Look at the properties for P355NH material. At 50OC, Rp0.2/t is 343 MPa, yet at 20OC, the value is 355 MPa. So the important point here, is that a value of Rp0.2/t is available for 50OC. In the case of P355NL1 material, no value is available for 50OC. This presents us (COADE) with a problem. We have no guidance as to what to do in this case, as we need a value for 50OC. So this is what we did:

We went to EN 13480-3, the piping code. In paragraph 5.2.5.2 we found the following information (click on the EN13480-P355NL1.gif at end of the message):

So, I applied this paragraph as a very conservative measure to get this (entable.gif):

This is the approach we took. We have not allowed temperatures above 150OC. I do not say this is the correct approach, but it is the conservative approach. Now let us look at EN 13445-2 Paragraph 4.2.2.1:

Table 4.2.1 is in my opinion not applicable (although I could be wrong). Paragraph 4.2.2.1 mention: .. two adjacent values... We do not have two adjacent values for P355NL1, so it appears to me that we cannot apply the table. I would like really to see a statement such as: Multiply the strength factor by ReH. This is not how I interpret 4.2.2.1.

As I stated, I could be wrong, but I am in a grey area, and I erred on the conservative side.

Now, you have the facility of putting P355NL1 as a custom material in the user material database, in which case you can have the values you computed per you attached sheet. I do not see any objection to this. However, if someone can give me a definitive statement that Table 4.2.1 can be used based on ReH then I would be only too happy to change the programme. We only want to be correct.

Please let me know your feelings on the matter. I am always willing to listen.


Attachments
294-P355NL1.gif

296-EN13480-P355NL1.gif

297-entable.gif


_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#18163 - 05/21/08 06:29 AM Re: EN 13445 material database [Re: Ray_Delaforce]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
We have changed the method of computing EN materials whose elevated temperatures are not available. We now use EN 13445-2 paragraph 4.2.2 and Table 4.2.1. Using this method, the stresses are available up to 300 C.

This replaces my comment above.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#18642 - 06/16/08 03:28 AM Re: EN 13445 material database [Re: VesEng1]
IgnacioMPereda Offline
Member

Registered: 03/25/08
Posts: 19
Loc: Spain


Hi VesEng1,

i didn't notice about your question, but i will take a look, thanks for the post.

However, i am seeing that the difference in required thickness is very little whatever is the material yield strength (if they are not very different,for example 20% because the most important variable is the E value, at least in spherical heads).

What i really wonder is why european code is much less conservative than ASME VIII, when calculating spherical and torispherical heads? Maybe, you have some valuable experience in this field.

Thanks in advance

Ignacio

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