2 replies to this topic

Hi all,

I need to determine to the wall thickness required of a pipe. Pressure inside the pipe is 15barg, outside pressure is atmospheric and the material of construction is 25Cr/20Ni HK 40 Alloy. I have no mechanical engineering knowledge so any help is much appreciated. A good book recommendation would also be helpful as i need to reference where my new mechanical engineering skills have come from.

Thanks

[aliadnan]

Hi

For some introduction of Mechanical Design read "Coulson & Richardson Vol-6". It has some basics on this topic and you will get the formula from there. The following book is highly recommended by Mr. Art for the Mechanical Design

“Pressure Vessel Handbook”
by Eugene F. Megyesy
Pressure Vessel Handbook Publishing, Inc.
P.O. Box 35365
Tulsa, OK 74135

For cylinderical Metal shell use the formula

t = PR/(SE – 0.6P)

where,
t = cylindrical wall thickness, inches
P = Design pressure, psi
R = Inside cylindrical radius, inches
S = Stress value of the metal material, psi
E = Joint efficiency of the welded sections, expressed as a fraction


Hope this Helps

Regards
Ali

[Art Montemayor]

William:

I'm glad to see so many young engineers interested in the mechanical engineering area of pressure vessels and design of piping. If you enter the arena of plant or process design engineering you will certainly need or have a need for understanding and working with this knowledge.

I'm going to assume that you are serious in your endeavor and I'm going to offer you some information to help you out. Firstly, you can easily find the allowable design stress for HK-40 in the Internet by going through Google's search engine. Key in HK-40 and follow up with the related key of allowable stress.

Also, go to:

pveng.com

and download all the free design spreadsheets they offer you for vessels, heads, pipes, and other mechanical designs. I'm attaching a sample of the type of mechanical design information you can obtain there.

I hope this helps you and others out in understanding and working with pressure vessels and their design. A pipe is very similar to a pressure vessel.

Art Montemayor  PipeAndShell21.zip   61.2KB   342 downloads