Max thickness / high pressure

[bermut]

Is there as per ASME VIII div 1, any relationship between the maximal thickness of metal sheets for a pressurized vessel and its diameter. I need to make the design of a CS drum of 387.9 bar g / 93.3°C design conditions. Diameter is 1625 mm / height = 3000 mm TL to TL
The thickness is expected to be very high. Is there a maximal thickness for the shhet of metal used to built this vessel or do I need forged material ?
Thanks

 

[Amsterdam]

Dear Bermut,

You are out of the scope of Section VIII Div.1, see U-1(d) pressures exceeding 3000 PSI. So try Div. 2. Still it is possible to keep your vessel in Div. 1 but you need to preform some additional calculations at the satisfactory of your AI.

Good Luck,

Gert

 

[prex]

Generally speaking there is no limit as to the thickness of formed plates: limits exist for the degree of cold forming, but hot forming or a suitable heat treatment will do.
However check the new Div.3 of ASME VIII for high pressure vessels. prex

http://www.xcalcs.com

Online tools for structural design

 

[JamesBarlow]

The allowable thickness of any given material will be determined by the information in Section 2.

The information you get from Section 8, div 1 will just tell you how thick of a wall you need. I don't have any knowledge of Division 1, but I know for Division 3 the materials I can select from are limited. We are making a vessel right now with a 14" wall thickness. I may be able to find a 14" thick plate, but if Section 2 says that for this material I am only allowed to have it 2" thick then I must look for a new material.

Specifically for Division 3 all of my vessels are forged using SA-723. For nearly 30 years the company has been making vessels out 4340, forged and heat treated, however section 2 only allows 4340 to be used as bolting material.

 

[kyong]

I don't think Section VIII Div 1 Code itself doesn't limit the design pressure. With the pressure, however, Div 1 gives a little thicker thickness than the thickness of Div 2 calculation. As long as I know, SA516-70(normalized) is produced up to 8" and the maximum thickness of this material looks just good to that design pressure when Div 2 calculation is applied. But I think you need to check if the plate that thick is actually available in the market. And rolling and welding also will not easy. And if your company is not liscenced to manufacture by Div 2, you might not able to use the result of Div 2 calculation. I am not familiar with very thick pressure vessels. If I am wrong, correction would be welcomed.

kyong

 

[PAN]

Amsterdam,
I agree with kyong. ASME Sec. VIII Div. 1 can be used for more than 3000 psi. However, Div. 2 is more economic. Please comment.

 

[Dikkala]

It is better to use multi-walled vessel for very high working pressures.

 

[davefitz]

ditto.
I think the section VIII rules refer to a different design code or appendix for diameter ratios above some value, perhaps 1.6:1

The wiser method is to use a ribbon wound multi layer pressure vessel, as used in ammonia reforming work overseas. Unlike monolithic vessels, a crack will not propagate to vessel failure in a mulit layed vessel, and the thernal stresses are bounded to lower values. Also, the lead time is MUCH shorter.