SA-249 (ASTM A262)

[AJLis]

Background:
I have a heat exchanger with SA-249 TP31600 tubes that I'm looking to replace in-kind. It does not have the best equipment records, so intergranular corrosion may, or may not, be an issue. Per SA-249, a supplementary inspection is to test for intergranular corrosion per ASTM A262 Prac. A/B/C.

Question:
Would original MTRs for the tubes list if ASTM A262 Prac. A/B/C was completed? Please let me know if more info is needed.

 

[EdStainless]

It should note that.
If you are replacing is there any reason not to use 316L?
I would suggest also requiring S-7 (supplemental requirement, weld decay testing) with ratio not to exceed 1.0
Make sure that they really are solution annealed.

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P.E. Metallurgy, Plymouth Tube

 

[Dhurjati Sen]

Dear AJLis,

You have supplied very little info. Why should it be inter-granular corrosion?

If you want an IGC test to be done on the tubes, simply go ahead, you will get better and costly tubes.

Good luck.

DHURJATI SEN

 

[AJLis]

Thank you for the replies, gentlemen. There are no notes on the initial material inspections and I'm not a materials expert.

EdStainless,
I need to keep the material (316) the same to keep the project on a maintenance budget, not capital dollars. The original HX lasted 20 yrs, so I need the same life.
- Is S7 a replacement test for ASTM A262 Prac A/B/C?
- Besides the MTR stating solution annealed, what can I do to verify?

Dhurjati Sen,
Honestly, I have no idea if inter-granular corrosion is a possibility. The process sides are both gas, and contain acetic acid (20%) and vinyl acetate (13%) on the tube side. Neither side sees temps that are above 190C. The tubes are rolled to the tube sheet, not welded.

 

[EdStainless]

AJL,
The S-7 and A262 test for different deficiencies and both should be required.
Unless your design is right on the limits moving from 316 to 316L should not cost any money or time.
Remember if you require A262E the first step says 'do pract A and if it is OK let it pass', we have many customers that require the corrosion test regardless of what the micros look like.
Any decent mill will include S-7 (even at r<1.0) and A262 for little added cost. These are common requirements.

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P.E. Metallurgy, Plymouth Tube

 

[AJLis]

Ed,
Thank you for your input. I don't have access to A262, so I'm flying blind. I've asked the heat exchanger manufacturer to quote (cost and time) S7 and A262E testing for the heck of it. I don't have any senior resources at work, so I learn by 'doing' where ever I can. Thanks!

Side note: I was on the phone with a few people at Plymouth Tube Co. this morning asking questions regarding A262 and older MTRs for this exact job. Everyone has been very helpful.