A-105 Flanges Normalized and Produced to Fine Grain Practice

[wsmith22]

Are these flanges readily available or would it be better to use SA-350 LF2 material? Our flange distributors cannot locate flanges that meet the fine grain practice requirement per SA-20.

Thank you.

 

[r6155]

SA-20 is for plates.
See Referenced Documents in SA-105. Read SA-105 in full.

Regards

 

[wsmith22]

Yes, it is confusing because Figure UCS-66 General Note (d)(2): fine grain practice is defined as the procedure necessary to obtain a fine austenitic grain size as described in SA-20.

 

[weldstan]

Yes they can be made and purchased with a fine grain melting practice and a normalizing heat treatment; however, this does not insure meeting -50F impacts.

 

[Guest102023]

SA-20 is for plates.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[weldstan]

And the fine grain melting practice does not have to meet SA-20 guidelines. Withot knowing, you may get soemething you really don't want. If you need high impat toughness below -20F, buy the appropriate SA-320 grade forgingss. There are other parameters besides normalizing and fine grain melting that must be taken into account by the forging manufacturer to achieve low temp toughness.

 

[staticmh]

As per B16.5 SA-105 flange can be withstand up to maximum -29 deg C. Hence as per your desired -46 deg C MDMT it shall not be work.

Further to regarding the normalized / fine grain practice, this has been revised in ASME SEC VIII Div. 1 2019 ver., now the SA-105N is coming under the curve B earlier it was in curve A.

However, I would recommend you to go for the SA-350 LF2 CL. 1 material straight away without worrying and also to avoid the any inconvenience in the future by ASME Auditor.

 

[SJones]

Where does the low temperature requirement come in? The OP has mentioned nothing about temperature.

With respect to A105 being allowed to go automatically to -29 deg C, people might want to think again about that. Take a look at:

https://docplayer.net/48868523-Ncpwb-technical-bulletin-may-2016.html

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[Strook]

From my understanding of ASME BPVC Section VIII Div 1 2019, UCS-66,

ASTM A105 is permitted to -8C, ASTM A105N is permitted to -29C, and ASTM A350 LF2 Class 1 is permitted to -45C.

The revision in 2019 was brought about by failures in A105 flanges at temperatures warmer than previously permitted -29C and I also understand there remains some concern still, hinting at further reforms to the use of A105 at low temps. I generally opt for A350 LF2 Class 1 for all flanges below 0C now, based on performance, availability and anticipation of further reforms.

 

[GD2]

wsmith22,

Let's try another way. If it's for a piping system , what's the piping class? The piping class should give you the temperature limits. If not, give us some design/operating conditions to guide you if SA350 LF2 flanges are a good fit for A105N. In general, grain refinement gives higher impact strength resistance and allows to use for lower temperature. SA 350 LF2 are used in low-temp service conditions.

GDD
Canada