Inconel 600 and Inconel 625

[sw007]

For some reasons, we can not find the 321SS or 347SS bolting materials. Our client indicated that we can use Inconel 600 or Inconel 625 in lieu of 321SS or 347SS as the bolting materials.

The service condition:
Desgin temperature: 430 C;
Maximum Operating Temperature: 400C

Hydrogen Partial pressure: 2500Kpa (a)
H2S concentration in vapor phase:1200ppm

Is it ok to use alloy 600 or alloy 625?

what is the limitation to use alloy600 and alloy 625?

Thanks.

 

[EdStainless]

I would prefer 625.
The only limitation is money.

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Plymouth Tube

 

[metengr]

sw007;
Are you going to use a bolting specification for this application? This sounds like a pressure vessel or piping, and if it is, use an appropriate ASTM/ASME material specification for purchasing, and not just an alloy trade name.

ASME SB 166 UNS N06600
ASME SB 446 UNS N06625

You should review the allowable stress values in ASME B&PV Code, Section II, Table 3. For UNS 06600, the allowable stress at 400 deg C is around 19-21 Ksi. In comparison, for UNS 06625, the allowable stress is 26 Ksi.

For more background regarding both alloys, I would visit the web site below;

http://www.specialmetals.com/products/index.php

 

[sw007]

EdStainless, metengr;

Thanks for your comments.

Yes, this is for heat exchangers floating head cover. I have already checked the allowable stress valuess. One of the reasons we use alloy600 and alloy625 is the high allowable stress values of these two alloys at high temperature.

I just want to make sure these two alloys can be used in these conditions.

 

[unclesyd]

Here is a little information if still need the 321SS or 347SS fasteners.

I just got off the phone with Ameribolt, fastener distributor, concerning another bolting supply problem and during our conversation I mentioned the fact you were
unable to get a quote on 321SS or 347SS studs. He stated that if you still need these materials send an RFQ, attention Mike. He said that if he can't supply them he will direct you to someone that can.

Toll Free 866-390-8990

Toll Free Fax 877-378-0134

http://www.ameribolt.com/

 

[strider6]

sw007

you mention the partial pressure of H2S. This bolt material will see the process side, it will be exposed to H2S and 400°C.? If you are under the requirements of Sour Service (NACE/ISO) then i think that you've to take into account the partial pressure and temperature limit for the materials tht you want to use.
what is the material of the exchanger?
S.

Corrosion Prevention & Corrosion Control

 

[sw007]

unclesyd: Thanks for your information. The vendor is not in the United State.Probably they would like to order the materials in their country.


strider6:

The exchange shell side is 1.25Cr with 321 clad.


Are their any other cheaper bolt materials which can be used in this condition? How about SA453 GR 660?

 

[strider6]

what kind of plant is? Refinery? Oil&Gas?

S

Corrosion Prevention & Corrosion Control