Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Inconel 718 suitable for amines service ?

Status
Not open for further replies.
Sort by date Sort by votes
718 has lower corrosion resistance than 625, and in 718 it may depend on the HT condition. There are three different aging treatments so be careful.
Why would you want to use 718?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
Upvote 0 Downvote
Edstainless, the reason for 718 is due to the strength. I need a material that has min 105K yield. The HT condition of the 718 in question would be solution treated and precipitation hardened per NACE MR-01-75.
 
Upvote 0 Downvote
Have you looked at 725? Or even work hardened 22 or 686?
What product form are you looking for?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
Upvote 0 Downvote
EdStainless, I just read up on the materials you have mentioned. It looks like 725 has similar corrosion properties as 625 with higher strength, which per the document in my initial post would be suitable for rich amines service. I'm a bit confused on why in lean amines the material is not suitable? Would 686 work with lean amines service as well?

Product form: bar. Will be used for the valve stem.

Thanks for the support!
 
Upvote 0 Downvote
There's a whole raft of high strength nickel alloys developed for high pressure systems that are, more or less, standard materials for subsea production systems: 716, 718, 725, etc, etc - the complete menu is in API Std 6ACRA which should be your go to document. Never seen them in a gas sweetening unit before, and not noted in European Federation of Corrosion Publication 46. Is super duplex stainless steel not an option - a bit less aggravation on the manufacturing quality control front, and more suppliers are likely to have Norsok M-650/ISO 17782 documentation. Of course, you will only get 80 ksi, but it may be quicker and easier.

Steve Jones
Corrosion Management Consultant


All answers are personal opinions only and are in no way connected with any employer.
 
Upvote 0 Downvote
Hi SJones, I did look into some super duplex stainless steel, but strength did not meet the requirement(105k Ksi). Like you have mentioned, they are mostly limited to 80Ksi. I will look into API Std 6ACRA.
 
Upvote 0 Downvote
Out of interest, why does it have to be 105 ksi in a gas sweetening unit?

Steve Jones
Corrosion Management Consultant


All answers are personal opinions only and are in no way connected with any employer.
 
Upvote 0 Downvote
SJones, the material is used for a valve stem, which requires 105 ksi.
 
Upvote 0 Downvote
Yes - you said that, but what pressure is this system working at to demand that sort of strength?

Steve Jones
Corrosion Management Consultant


All answers are personal opinions only and are in no way connected with any employer.
 
Upvote 0 Downvote
The pressure is 1480psig. The torque to operate the valve is high due to the application and seat materials.
 
Upvote 0 Downvote
I would look at cold worked Ni alloys.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

ShabsRBI
  • Locked
  • Question Question
Pump body for Sour Water Service
Replies
7
Views
2K
LittleInch
LittleInch
Kabootarman
  • Question Question
Soft Seats in Acid Gas service
Replies
1
Views
3K
SJones
SJones
V
  • Question Question
PE/PP in Concentrated Sulfuric Acid Service
Replies
2
Views
4K
Vahid.A
V
kondori
  • Locked
  • Question Question
Inadequate PWHT holding time for Carbon Steel piping in caustic service (NACE SP-0403)
Replies
16
Views
9K
kondori
kondori
awesomeness
  • Question Question
Effect of microstructure on crevice corrosion for SDSS
Replies
5
Views
16K
weldstan
weldstan

Part and Inventory Search

Sponsor

Back
Top