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!

*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.

Jobs

Material

Material

(OP)
if a pipe and flange is of carbon steel, then orifice plate (to be installed in that pipe/flange) will be of carbon steel or any other material (Stainless steel etc) can be used ??

John120

RE: Material

Stainless steel is typically used for orifice plates.

RE: Material

You can use anything you like so long as it is compatible wuth the fluid.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Material

(OP)
In case of Carbon steel flanges with Stainless steel orifice. Any risk of corrosion ?

John120

RE: Material

2
Leo165...

If you are referring to galvanic corrosion between CS and SS, there is a very low corrosion potential between the two materials..... Virtually no corrosion between the two.

Additionally, the orifice gaskets tend to electrically isolate the two materials.

MJCronin
Sr. Process Engineer

RE: Material

3
Not so sure about low corrosion potential, but the area ratio would seem to be in your favour. Basically a small STl Stl item in a much larger C Stl environment, even with conductive liquid, water and oxygen present the corrosion of the C stl element would be very low.

The other way around, i.e. small C stl element in a Stl Stl one where galvanic corrosion can occur can eat C Stl very quickly.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Material

(OP)
Sir "Bimr", What about Carbon steel orifice plates ? Why they are less used (you are right but I am looking for some reasons, why not carbon steel orifice with carbon steel flanges) ?

John120

RE: Material

3
IMO, if having a general corrosion in the CS orifice hole as typically happened, the flow measurement will be inaccurate without noticed.

RE: Material

It is not uncommon to see orifice plates in Ni alloys (over the years I have also seen Co alloys and ceramic).
You need something that will nearly zero corrosion and erosion in your media, at velocities much higher than the pipe sees.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Material

Corrosion products from the CS orifice plate may choke and hence distort the readings of the instruments to which the orifice flange is connected. So an SS plate is generally used.
Galvanic corrosion between the CS piping and SS orifice plate is negligible. However, carbon pick-up by the SS plate could be an issue. Always better to use a low carbon SS.

RE: Material

The cost of the material is a small part of the fabrication cost of the orifice plate manufacturing process. The cost difference between the carbon steel and stainless steel orifice plate is small.

Following careful shearing, squares of sheets are machined/laser cut to circular discs. Other methods such as stamping or burning the plate blanks are relatively inaccurate. Plates are typically finished to 15-30 micro-inch roughness, applied by special sanding machines designed to preserve the flatness of each plate. Fabrication methods avoid procedures which may damage the bore accuracy or the plate finish.

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close