Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
-
Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
MATERIAL SA36 2
- Thread starter GIGI72
- Start date
-
1
- #2
JStephen:
Guess I have just seen to many quality problems in the use of a structural steel in a vessel application.
Sometimes it will not matter,per UCS-6,but I do not agree that it is most common for vessel application.
Cheaper is not always cheapest. I could tell you a number of poor result stories for A-36 but would need a new page.
INMHO: Angle,channel,non-pressure,its...OK,but for anything else...be careful.
Guess I have just seen to many quality problems in the use of a structural steel in a vessel application.
Sometimes it will not matter,per UCS-6,but I do not agree that it is most common for vessel application.
Cheaper is not always cheapest. I could tell you a number of poor result stories for A-36 but would need a new page.
INMHO: Angle,channel,non-pressure,its...OK,but for anything else...be careful.
-
1
- #11
As an engineer who directly specified or was involved in specifying materials for well over 1000 pressure vessels for use in the petrochemical and power industries, I can only think of one or two which was specifed as being manufactured from SA-36.
As an old steel maker, I can attest to the downgrading of many heats of other steels into A-36, which was the "catch all" for downgrades. In the past, the liklihood of laminations in A-36 plate was quite high, and the toughness of the material was especially low in the downgraded heats.
As an old steel maker, I can attest to the downgrading of many heats of other steels into A-36, which was the "catch all" for downgrades. In the past, the liklihood of laminations in A-36 plate was quite high, and the toughness of the material was especially low in the downgraded heats.
I can only assume that the pressure vessel committees disagree with that assessment. Note that A36 does use lower allowable stresses, and does have different treatment for notch toughness than A516-70. So while a mill might downgrade a batch of A516-70 into A36, it wouldn't be designed like it was still A516-70, either. For that matter, a mill could downgrade some higher-strength plate into A516-70, but that wouldn't be a reason to avoid A516-70 in use. In the applications I'm familiar with, I'm not aware of any quality problems with A36 specifically. I've seen similar statements made on US-vs-domestic plate, and haven't really seen a trend there, either.
As to which is actually most common, I think that would have to depend on the experience of the user. I recall talking to one vessel fabricator that made virtually all their vessels from pipe. Or if you're using anything much over 1/2" or 3/8", it's going to be more economical to use A516-70 or some other material anyway, because of the higher allowables. F&D heads are commonly stocked in A516-70, and may or may not be available in A36. I'll bet half of all the ASME vessels in existence are air compressor tanks or propane tanks, and that would certainly skew the statistics to whatever those people use.
By the way, I recently saw a little aluminum air tank for sale (pressurize it, then use it to air up tires- maybe 5 or 10 gallons). Boldly stenciled on it was "Do Not Drop". That, to me, is scary.
As to which is actually most common, I think that would have to depend on the experience of the user. I recall talking to one vessel fabricator that made virtually all their vessels from pipe. Or if you're using anything much over 1/2" or 3/8", it's going to be more economical to use A516-70 or some other material anyway, because of the higher allowables. F&D heads are commonly stocked in A516-70, and may or may not be available in A36. I'll bet half of all the ASME vessels in existence are air compressor tanks or propane tanks, and that would certainly skew the statistics to whatever those people use.
By the way, I recently saw a little aluminum air tank for sale (pressurize it, then use it to air up tires- maybe 5 or 10 gallons). Boldly stenciled on it was "Do Not Drop". That, to me, is scary.
IJStephen,
With regard to your statement, "I can only assume that the pressure vessel committee disagree with that assessment", I think not, noting the further limitations put on its use relative to that of SA-516, SA-285, SA-515 (to name but a few) and other carbon steels. ASME Section I will not permit SA-36 plate in vessel or boiler construction. ASME VIII restricts its use to a maximum temp of 650 F and similar restrictions are invoked in both ASME B31.3 and B31.1 piping codes. On the contrary, ASME committees have been fully aware of the limitations of SA-36 and have made appropriate provisions.
With regard to your statement, "I can only assume that the pressure vessel committee disagree
Stan, my point is that you and some others seem to be saying that SA 36 should not be used even within those restrictions, whereas the committees allow it to be used within those restrictions. If I understand you and deanc correctly, you'd be considerably more restrictive than the code is on the use of SA 36. IE, viewing a vessel designed and constructed 100% within the code as "scary" is certainly not what the code writers are thinking.
JStephen:
I have no issue with what you are saying and if the Code allows a material and someone wants to build...so be it.
Over the years I have seen a number of problems with A-36 in PV use,,,,I just think there are better choices.
"Cheap" is not always the best answer. Pay up front or pay in back...nothing is free.
I have no issue with what you are saying and if the Code allows a material and someone wants to build...so be it.
Over the years I have seen a number of problems with A-36 in PV use,,,,I just think there are better choices.
"Cheap" is not always the best answer. Pay up front or pay in back...nothing is free.
JStephen,
I echo deanc's last comments and add that if one purchases SA-36 correctly, you can obtain SA-36 with quality equivalent to SA-515 or SA-516 or of slightly lesser quality that will certainly meet design/safety requirements for air receivers and propane/LPG bottles, etc. without adding to manufacturing woes.
I was also pointing out that if one intends to use SA-36 in vessel/ heat exchanger construction for the petrochemical and power industries, one should think again.
I echo deanc's last comments and add that if one purchases SA-36 correctly, you can obtain SA-36 with quality equivalent to SA-515 or SA-516 or of slightly lesser quality that will certainly meet design/safety requirements for air receivers and propane/LPG bottles, etc. without adding to manufacturing woes.
I was also pointing out that if one intends to use SA-36 in vessel/ heat exchanger construction for the petrochemical and power industries, one should think again.
I am not sure why anybody would like to risk the use of questionable quality material on vessels.
The mentioned UCS 6 (b)(1) suggests that the vessel may leak. I agree that SA-36 may meet the SA-516 strength but also it may not. Lottery or russian roulette? I don't want it in my vessels.
Putting Human Factor Back in Engineering
The mentioned UCS 6 (b)(1) suggests that the vessel may leak. I agree that SA-36 may meet the SA-516 strength but also it may not. Lottery or russian roulette? I don't want it in my vessels.
Putting Human Factor Back in Engineering
It isn't intended as an equivalent substitute for SA-516-70. It doesn't need to meet the SA-516-70 strength requirements, it needs to meet the SA 36 strength requirements. SA 36 is a separate item with specified allowable stresses.
You might note that the lower grades of SA 516 won't necessarily meet the SA-36 strength requirements, either. That's not a reason to avoid them, just different materials for different applications.
If you're in the petroleum business (as I judge by your name), you probably already have acres of SA-36 plate in service in your atmospheric tanks.
You might note that the lower grades of SA 516 won't necessarily meet the SA-36 strength requirements, either. That's not a reason to avoid them, just different materials for different applications.
If you're in the petroleum business (as I judge by your name), you probably already have acres of SA-36 plate in service in your atmospheric tanks.
- Status
Similar threads
- Question