×
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

Ball Valve Body Material

Ball Valve Body Material

Ball Valve Body Material

(OP)

LPG piping design temperature -45 deg c to 50 deg c and design pressure 40kg/cm2 g
And material for this line is A333-6 SEAMLESS

Valve vendor want to supply
Ball Valve Body material ASTM A351 Gr.CF8M can use instead of A 352 Gr.LCB
Ball Valve Body material ASTM A182 Gr.F316 can use instead of A 350 Gr.LF2

It is acceptable or not.
what is advantage and disadvantage?



RE: Ball Valve Body Material

You original specs are carbon steel materials which undergo impact testing to prove that they do not suffer excessive loss of toughness which can result in brittle fracture. These are usually required for low temperature applications, as your service is at -45 deg C.

The vendor specifications are for 316 Stainless Steel bodies, which are usually not susceptible to brittle fracture, thus are not required to be impact tested.

Your advantages are less change of brittle fracture and also minimal corrosion.

Your disadvantages would be the increased cost of the valve and the introduction of dissimilar metal contact surfaces which may be a point of galvanic corrosion.

RE: Ball Valve Body Material

If your supplier sells teh stainless steel at the same price as the LCB or LF2, then that is very good for you.

There is a slight reduction in pressure rating for the stainless steel, but it is ususally insignificant.

Chances are the supplier has the stainless steel material on the shelf and can deliver much quicker than if they have to order LCB or LF2 castings from a foundry. So I expect you will see a shorter delivery time.

This material substitution is common and is normally OK. The LCB abd LF2 valves most likely have stainless steel trim inside so material compatibility should not be a problem.

RE: Ball Valve Body Material

(OP)
Dear RipZ

For dissimilar metal contact surfaces which may be a point of galvanic corrosion.

To avoid Galvanic corrosion pikotek gasket can use known (to isolate two dissimilar contact surface)


Thanks

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