×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Difference in Head and Shell Thickness
2

Difference in Head and Shell Thickness

Difference in Head and Shell Thickness

(OP)
Hi All,
I'm supervising pressure vessel Manufacturing Project(Three phase Separators) and noted difference in Head and Shell thickness and on enquring from vendor he replied, "The head thickness given is Minimum, after considering thinning allowance for forming. the nominal thickness for both shell and head at joint would be the same"
can any one explain me this further on thining allowance forming, thining allowance from what?
Thanks
10815L

RE: Difference in Head and Shell Thickness

Heads are formed (cold worked) from blanks (shaped like a blind flange). The thickness of the formed head will be less than the original blank; i.e. it thins. Vessel fabricators do this so often, they know how much the thinning should be (thinning allowance).

Good luck,
Latexman

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

RE: Difference in Head and Shell Thickness

The head manufacturer adds a thinning allowance to the heads to ensure that the finished heads meet the minimum thickness in all areas. During the head forming process, the metal does not disappear but may flow to the areas that are most worked. On a spun head, the flange may get thicker and the knuckle will get thinner due to cold working.

RE: Difference in Head and Shell Thickness

This is a question that should be asked in the "Boiler and Pressure Vessel forum"....better answers there

RE: Difference in Head and Shell Thickness

I'm not an expert in this area, but I would assume that the metal is made as thick as it needs to be for the service. The stress in the cylindrical shell due to pressure (hoop stress) is twice the stress in a hemispherical head. So less metal can be used in the head.

RE: Difference in Head and Shell Thickness

(OP)
Hi,
Thanks a lot for good explannation, particularly Latexman for sharing good video.
10815L

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources