A193 B7 at - 50F Application

[SNSR]

This is probably an old question and has been asked several times. Seen the threads, and the usual response is A193 B7 is limited to - 29deg C. That's fair, All major oil companies do not use A193 B7 beyond -29C. Likewise the internet. I searched thru numerous websites including valve manufacturers, and they application is consistent with major oil companies.

However I looked up B31.3, Table A2 I believe, and it allows use of A193 B7 for dia below 2.5" upto - 55F, and for diameters above 2.5", -40F.

Based on that, there should be no problem using these bolts up to - 50F depending on its diameter.

Can someone please shed some light as towhy there is a general preference to avoid using A193 B7 below - 29 deg C in the industry?

Thanks in advance.

 

[LittleInch]

It's all about note 6

*The minimum temperature shown is that design minimum
temperature for which the material is normally suitable
without impact testing other than that required by the material
specification. However, the use of a material at a design
minimum temperature colder than −29°C (−20°F) is established
by rules elsewhere in this Code, including
para. 323.2.2 and other impact test requirements. For
carbon steels with a letter designation in the Min. Temp.
column, see para. 323.2.2(e) and the applicable curve
and Notes in Figure 323.2.2A.

That makes it a pain in the ass compared to buying bolts which are ready certified and more suitable like A320?
Basically the same material, but already impact tested at -15F / -101C

A few came up on search like this

https://www.eng-tips.com/viewthread.cfm?qid=237615

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SNSR]

Hi LittleInch, the note you mentioned, I believe has been amended now in B31.3 2022 edition. The part where it mentions below - 29 deg C has been removed. It's a different game now, it appears. Please refer to Note 3 and let me have your thought. Thanks.

 

[r6155]

Can someone please shed some light as towhy there is a general preference to avoid using A193 B7 below - 29 deg C in the industry?

Since the studs are interchangeable parts, I need to have B7 in the stock in warehouse that can be used on piping or pressure vessels.
Therefore, to avoid errors, some manufacturers limit the B7 to a temperature no colder than -29°C

Regards