SA515 Gr 70 and SA516 Gr 70

Mag · **Joined:** Wed Jul 13, 2011 9:41 pm **Posts:** 2

Dears,
It is the first time to join this powerful technical forum, please accept my joining where i will help and share my experience and get support of this technical hub.
It's my first question i hope it is in the right section.
We have waste heat boiler (firebox boiler), the shell has MOC SA515gr70 while the tube sheet is formed plate of SA516gr70, during startup, double jeopardy has occured and experienced short-term overheating leaving adistortion to tubesheets and shell, tubes have sagged. We are running FFS level III, looks no promise, fabrication shop does not have SA515gr70. It is S-stamped
can we use 516gr70 instead (why difference in first place)

Any help would be greatly appreciated.

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

Mag wrote:

Dears,
It is the first time to join this powerful technical forum, please accept my joining where i will help and share my experience and get support of this technical hub.
It's my first question i hope it is in the right section.
We have waste heat boiler (firebox boiler), the shell has MOC SA515gr70 while the tube sheet is formed plate of SA516gr70, during startup, double jeopardy has occured and experienced short-term overheating leaving adistortion to tubesheets and shell, tubes have sagged. We are running FFS level III, looks no promise, fabrication shop does not have SA515gr70. It is S-stamped
can we use 516gr70 instead (why difference in first place)

Yes you can use SA 516 instead of SA 515.
SA 515 is coarse grain whilst SA-516 is fine grain (see SA-20 for definitions). Coarse grain was supposed to be more resistant to creep. It has been demonstrated that SA-516 has the same creep resistance. Therefore SA-516 may be used where time ago SA-515 was recommended. No problem by Code point of view, as well.
mauro
I could see in

Any help would be greatly appreciated.

Javed Nasir · **Posted:** Sat Jul 23, 2011 8:53 pm

SA-515 grade 70 and SA-516 grade 70 have almost same creep properties that is why Notes G10,S1 and T2 are common to both in Table 1A of section II-D.
SA-516 grade 70 has better impact properties as compared to SA-515 grade 70 as we see UCS-66 Curves because SA 516 grade 70 has fine austenetic grain structure.
Code requires 515 grade 70 be normalized over 50 mm in thickness whereas this limit is 40 mm for SA-516 grade 70.
In Section I construction, SA-515 grade 70 may be used up to 538C while SA-516 grade 70 can only be used up to 454 C. But it shall also be remembered, to use these materials over 450 C is not advisable.

Javed Nasir · **Posted:** Sat Jul 23, 2011 8:57 pm

One point I like add more, the maximum allowable working stresses of both SA-515-70 and SA-516-70 are exactly the same at any design temperature within the limit of applicability.So thickness of both shall remain the same if all other design conditions do not change.

SA515 Gr 70 and SA516 Gr 70

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