SA-358 304L Cl.1 vs SA-312 TP304 for Low Temperature Service

[UW1981]

I understand the BPVC has a specific statement regarding the acceptable use SA-312 for use in low temperature applications and no such statement is made in regards to SA-358....and I realize the A-358 spec identifies this material for high temperature and corrosive service, but the B31.3 code identifies A-358 MDMT to -425 F, the same as SA-312 (assumes the A358 is solution treated)- and I also understand A358 is welded pipe whereas A312 can be seamless or welded, but given the B31.3 MMDT allowable, I would expect some folks use A358 - at least in large pipe diameters - for low temperature service. However, I can not find any specs (LANL, PIP, etc) that reference the use A358 in low temperature applications for piping system. What am I missing ? Thanx.[/b]

 

[Dhurjati Sen]

Dear UW1981,

You are using filler metal for welding in A358, the impact strength decreases, so the pipe is unsuitable to be used at low temperature.

Regards.



DHURJATI SEN

 

[GD2]

UW1981,
When thinking about BPVC, think about where you want to use the pipe. Example: SA 312 is not permitted in BPVC Sec III whereas SA358 in not permitted in Sec I, Sec VIII-1 and Sec X11. Moreover, not all permitted sections of BPVC allows use of SA 312 without impact testing.
On the contrary, ASME B31.3 allows to use both A312 and A358 upto -425F without impact testing. As you correctly said, A358 must be solution treated without which it will be limited to -20F without impact testing.

BPVC, B31.3, PIP, LANL are all different organizations with different Committees. These committees work separately and hardly work in unison.



GDD
Canada