Ravi, pl. have a look into the various API / BS stds to have an idea of various trim numbers and the base material types. And the various material specification classified by the manufacturing/fabrication method.
And you have to give your acceptance or decision on trim based on the Standard, the valve is designed and the trim no. specified in your specs.
For eg. look into API 594 page.10 table.3 for check valves.
Selection of trim itself is based on
1) Fluid service characteristics.(Velocity, liq.phase, gas phase, slurry type, corrosiveness and other special cases)
2) Leakage allowance / tighness requirement of the system like the ESD.
3) Torqing also controls the trim selection in case of MOVs.
4) Physical fabrication constriants.
5) Pressure/temperature rating.
6) Life of the trim due to service and functioning issues like clattering and slamming.
7) Not the least, valve size & the cost factor.
The above are to the extend I have faced in pratice.
However as a design engineer you are not prevented to use something not part of the standard trim table if your manufacturer proposes and you are satisfied in the best interest of your client. Sometimes you have to listen to the manufacturer as they are the specialist's in that subject.
With regards,
Kannan Sundaram.
| khalid iqbal <kiqbal9@yahoo.com> Sent by: materials-welding@googlegroups.com 25/02/2008 11:15
|
|
Dear Ravi,
If a steel contains 13% Cr. it means it is stainless Steel.
The material specifications provided by your vendor are adequate. You may even use SS304 grade.
Regards,
ravi kiran yeleswarapu <kiranry@rediffmail.com> wrote:
Gents,
Please share your views on following:
"As per specs valve trims are required to be of 13% Cr steel" no further details given w.r.t. material specs nor clarified with client then.
However vendor has supplied A276-316 for stem and A351 CF8M for disc.
Are above acceptable as per spec of 13% cr steel.
As per client's interpretation of 13% Cr steel means AISI 410 or equivalent but not 316.
Best regards,
Ravikiran
| Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. |
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding-unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
-~----------~----~----~----~------~----~------~--~---
No comments:
Post a Comment