DUPLEX AND SUPER DUPLEX STAINLESS STEEL 2

[EagerLearner]

Hi,

I am wondering how difficult is it to get these for orifice plate.
It seems that we have to wait for 2 wks or more to get a quotation from our supplier in Houston. This Duplex and Super Duplex also have to meet the requirements of DEP 30.10.02.35 EPE and MESC SPE 76/222

What is the difference between the DSS/SDSS and the 316SS in terms of meeting the DEP and MESC requirements? ie how difficult is it to follow the specs?

 

[gr2vessels]

The answer is trivial. First, price. Second, availability. The 316 should be off-shelf. The Duplex/Super Duplex is special order. In term or corrosion resistance, the DSS/SDSS are superior to 316SS. Also, just remember that not everyone has access to the DEP's.

 

[EdStainless]

The super duplex will have corrosion resistance similar to a 6%Mo super austenitic.
A standard 2205 duplex will be significantly more corrosion resistant than 316, more like 317LMN.

In addition with their higher strength the duplex alloys are far more erosion resistant than 316b even when there is no corrosion.

Are your plates a standard thickness? Buy a large sheet/plate and work from it.

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Plymouth Tube

 

[Hello000]

Duplex / Super Duplex are different than SS316. DSS / SDSS are selected because of service fluid requirement. Hence you can not go for SS316 instead of DSS/ SDSS just because of unavailability in market. However you can go for higher material orifice plate like 254SMO, Inconel625, HastelloyC276 etc. if available in stock.

Compare to SS316, DSS/ SDSS have different chemical composition, different grain structure, different heat treatment, different strength etc. and they additionaly require impact testing and ferrite measurement to ensure duplex structure.

 

[EagerLearner]

Thank you all for the information.

Our end user is requesting for such specifications and yes the DEP and MESC has been provided. I understand the difficulty in the materials but what i cannot understand is that to get a quotation takes like 2 wks or so. I mean they should already have a basis for the pricing for orifice plates as this is not the first time we have asked them to quote.

We tried to place order few times same materials of DSS or SDSS but size and class are different.
Plates are either 1/8" or 1/4" thickness.

 

[MJCronin]

What about the availabilty of an "uprated" material such as C276 instead of the duplex?

C276 should meet all corrosion resistance and strength requirements of your application..

You might be willing to pay a bit more for available C276 plate...

 

[EagerLearner]

Thanks MJCronin...

I dont really know much about materials. I dont know what C276 is but i will look up for more details.

Our end user normally request this for seawater apllication and they have provided their materials spec and all the flow cases to size the orifice so really i dont know if anyone in their companyhas ever looked at C276. Or maybe they have but find it not suitable. I dont know. But DSS and SDSS are also expensive.

May be i can suggest this or asked around.

Thanks again

 

[gr2vessels]

Eager, I was under the impression that you asked the suitability of Duplex and Super Duplex Stainless Steel for use under the requirements of DEP and MESC. Can you please add a title to the DEP number please? Also, is the DEP number correct?

 

[EagerLearner]

gr2vessels

DEP is correct. Title: Technical requirements for the supply of components in 6Mo Austenitic, 22Cr Duplex and 25Cr Super Duplex Stainless Steel.

Supplier gave us a reasson that because they need to review the requirements that's why it's taking them so long to provide us with a quote.

My questions is what i posted.