B16.34 2009 question 2

[reverman]

Tried this on The ASME board with no reaction thought I'd give this board a shot.

Did anybody attend any of the meetings?

I'm just wondering why the cast grade of 316L (A351 CF3M) and 304L (A351 CF3) moved tables and now have rated pressures significantly lower than 316 (A351 CF8M) and 304 (A351 CF8).

Both materials have identical physical property requirements. The only difference is the lower carbon content on the L grades. Per ASTM A351 you could certify all the L grade as the straight grade since there is not a minimum carbon content for the straight grade. So I see no reason for the change. The old revisions had a clause limiting the temperature on the L grade which seems fine to me.

 

[rneill]

Unfortunately, I don't have B16.34-2009 but I do have ASME B16.05-2009 as well as B16.5-2003.

In both B16.5-2009 and 2003, materials A351 CF3 and A351 CF8 are in materials group 2.1. Materials A351 CF3M and A351 CF8M are in materials group 2.2. This is identical to AB16.34-2004 but I don't have B16.34-2009 so I can't check it.

There has been no change in the assignment of these materials between 2003 and 2009. This suggest to me that any change in B16.34-2009 may be a mistake? Recommend you submit a code interpretation request, noting the discrepancy between B16.5 and B16.34, to the ASME committee.

 

[JLSeagull]

B16.34 2009
A 351 CFA, CF10 Group 2.1

CF8M, CF10M, CF3A, CF8A, CG8M, CG3M Group 2.2

A 351 CF3, CF3M Group 2.3

A 351 CF8C Group 2.5

A 351 CK3MnCuN, CD3MN, CE8MN, CD4MCuN Group 2.8

A 351 CH8, CH20 Group 2.10

A 351 CF8C Group 2.11

A 351 CK20 Group 2.12

A 351 CN3MN Group 3.12

A 351 CN7M Group 3.17

Unless I made a typographical or visualogical error.

 

[rneill]

Interesting, that means that in B16.34-09 both CF3 and CF3M have been moved to MG 2.3 but they have not been moved in B16.5-09.

I can't think of a reason for the two standards to have different pressure ratings for the same material (especially since they were published at the same time).

I can see some logic to having CF3M in MG 2.3 since that's where all the other 316L material is placed (e.g., forged and plate) but I don't see why ASME would change one standard but not the other.

Definitely worth submitting an interpretation request.

 

[reverman]

Forged A182 F316L has lower tensile and yield requirements than A182 F316 so there is logic for having it on different tables.

A351 CF8M and A351 CF3M have identical tensile and yield requirements so it doesn't make sense. It makes even less sense now that I see B16.5 did not change.

 

[rosta]

I noticed the same thing last week and came across this thread today.

Has this issue been resolved?

rneill:
Definitely worth submitting an interpretation request.

 

[JLSeagull]

A materials engineer advised that B16.34-2009 was being corrected for cast stainless steel valves with an addendum anticipated about now.

 

[rosta]

So does this mean the material goes back to its original group?

I just sent out an email to ASME concerning this issue. If I get a reply I will inform you.

 

[JLSeagull]

I have no idea what ASME will do. I also sent an email message to ASME regarding this issue. The ASME committees don't work for me; so I am not expecting a reply any time soon.

 

[rneill]

My prior interpretation requests have taken anywhere from 6 to 12 months to be answered so the addendum will probably be available before anyone gets an individual response.

 

[rosta]

It does take some time to get a response that much is true. However 6 to 12 months is a bit longer than I'm used to.

We've decided to stick to the 2004 version for CF3M material. How do you cope with this?

 

[rosta]

Just found this:

http://cstools.asme.org/csconnect/CommitteePages.cfm?Committee=N10061500&ProposalsSearch=yes

If you hit the "search this committee" button you can see:

09-1917 B16.34 - Material A 351 Gr. CF3M Out for Stds Comm Blt

Apparently it is officially accepted as an inquiry. Too bad we ca can't see what it is about.

 

[rneill]

Personally, I'd stick with the information in B16.5-2009 with regards to pressure ratings as this is consistent with the prior versions of both B16.5 and B16.34.

If a mistake was made, which is almost certain, then it is much more likely to be in the 1 document than the other three

 

[rosta]

Answer:
Your inquiry has been received. The committee is currently looking into this matter and as soon as an official correction to the issue is made, I will make it available to you.