Strength & Properties of ASTM A36 Steel at -40F 5

[SamCheung]

Why is it not suitable for -40DegF?

 

[SamCheung]

metengr,

I cannot find where the code specifically written that ASTM SA-36 is not permitted for constructing pressure tanks. From Table UCS-23, SA-36 is listed with ... which according to our QA/QC Engineer is OK to construct pressure vessels. From ASME code UCS-66, SA-36 falls on curve A of FIG. UCS-66 IMPACT TEST EXEMPTION CURVES. Any operating temperature below +20F is not exempted and in our case, our design is -40F. According to UCS-66, SA-36 is not IMPACT TEST EXEMPTED in our application, therefore my conclusion is an IMPACT TEST is REQUIRED for this material if it were to be used. Hence my qustion in the above posts is where to find the codes that contain the details on the impact testing of the tank made of SA-36 or is there a section on the detailed testing in the ASME codes at all?

Can some one also chime in on any impact testing details?

 

[doct9960]

SamCheung,

If you browse under CONTENTS of the "2 copies of ASME beside" you, you will find impact testing under UG-84

 

[SamCheung]

doct9960,

Thanks for the direction. You help ASME code dummies like me.

 

[unclesyd]

I have an old code book and in UCS-66 paragraph b:

"Vessels intended for service at temperatures below -20F shall not be constructed of materials complying with Specifications SA-7, SA-36, SA-113, or SA-283."

 

[SamCheung]

unclesyd,

Thanks for the info. Which edition you have? Both our editions allow SA-36 for limited pressure vessel use and one of than puzzles me why lethal (gas or liquid but not solids) uses are not permitted. I cannot see any correlation with lethal storages in SA-36 tanks. Is Aqua Ammonia classified as lethal under ASME code?

I invite all, pls feel free to comment if ammonia is lethal, or why lethal uses are not permitted in ASME codes, thanks.

 

[doct9960]

SamCheung,

Check the Material SAfety Data Sheet (MSDS) for your aqua ammonia. More than 500 ppm of ammonia is considered dangerous to life. If your tank contains such substance, SA-36 is definitely not permitted by the Code.

For the ASME definition of "lethal substance", refer to the footnote in UW-2

 

[unclesyd]

I actually copied the info from a 1965 Code book but I found the information first in my notes from a class taken in the mid 70's on low temperature design.

I'm hoping someone can trace this paragraph's lineage to see when the statement was changed or dropped.
One other old timers point is that materials at one time had to comply with ASTM A300, discontinued, and A-36 couldn't meet the criteria of A300 at the time.

I don't think aqua ammonia is classified as a lethal substance as we at one time had over 2 millions gallons of 27% in process. We used 2 different tanks that are still in process service, built 1965. I don't remember any particular precautions taken for this service. The only thing notable was that both tanks suffered from hydrogen blistering and has to be repaired before a change in service was effected.

 

[SamCheung]

doct9960,

OSHA 29 CFR 1910.1200 classified Aqua Ammonia as hazardous chemical. TSCA Inventry listed Ammonium Hydroxide as Toxic Substance and SARA TITLE III Section 302 classified it as Extremely Hazardous, but nothing described it as lethal!

I don't see why SS304 or SS316 is OK to store lethal substances while AS-36 cannot be used to store lethal substances, will someone be kind enough to explain to the puzzled mind, thanks.

 

[SamCheung]

unclesyd,

Thanks for sharimg the valuable experiences with SA-36 tanks in use of over 4 decades.

Any clue why hydrogen blistering occurs to these tanks. Is it hydrogen ion (dissociated from ammonia?) inside the tank attacking the ferrous materials of the tank? Could it be oxygen (from air due to tank emptying procedures?) attacking rather hydrogen attacked!

 

[SamCheung]

unclesyd,

Sorry you must have used other materials than SA-36. Do you know what materials are used to construct your tanks, thanks.

 

[unclesyd]

I'll try to find the material of construction of the Aqua Ammonia storage tanks. The storage tanks were equivalent to API 650 designed tanks. All of our Ammonia recovery equipment was CS of some vintage. I'll try to find the material of construction.
We are in Florida so low temperatures aren't a problem for storage tanks. The process equipment was designed to handle the auto refrigeration of the Anhydrous Ammonia.

 

[unclesyd]

The material for both Aqua Ammonia storage tanks in my previous posts is A-283.

 

[unclesyd]

Correcting my previous post the material is A 283 Grade C.

 

[JoeTank]

The toughness of A283-C is about same as A36. Both have very low toughness at temps below 0 degrees F.

Joe Tank

 

[SamCheung]

JoeTank,

Thanks for the info. Where can I find the toughness of A283-C, A36 and other low carbon steel toughness at low temperatures (i.e. at -40F) thanks.

 

[JoeTank]

Sam,
You won't find a tabulation of impact toughness for these grades. I've done the impact tests many times on a wide range of thicknesses and find that below about 20F that the impact test results will show ranges of 3 to 5 ft-lbs. This would be typical for A7, A283 and A36.

Joe Tank

 

[metengr]

Sam;
I have been watching this OP blossom. I would suggest you get your hands on two most important books that I believe will help you in your journey into understanding ASME Boiler and Pressure Vessel Code;

"The ASME Code Simplified Pressure Vessels, 7th Edition, by Robert Chuse and Bryce Carson Jr, Mcgraw Hill

"Pressure Vessel Design Handbook" by Bednar, 2nd Edition, Van Nostrand Reinhold

I have my own personal copy of each and they are tremendous resources.

 

[SamCheung]

metengr,

Thanks for the direction towards the great books. I will buy them myself if there isn't any available at our library.