6061 T-6 Aluminum in a the following gas environment? 1

[Metaldoctor]

I am looking to substantiate the use of 6061 T-6 as an actuator valve cap in the following environment:

79.5% Methane
1.55% Ethane
.35% propane

11.77% mole Nitrogen
6.35% mole Carbon Dioxide
.06% mole Hydrogen Sulphide

Dew point of gasses 8.0
Pressure absolute (psia) 264.6
indicated gage pressure (psig) 250

Would this environment pose a corrosive risk for 6061 T-6?

Any thoughts would be greatly appreciated.

 

[metengr]

After checking several sources, namely "Corrosion Engineering" by Fontana and "Corrosion and Corrosion Control" by Ulig, 6061 either O or in T4 or T6 tempers should be suitable to handle this gas atmosphere at ambient temperature.

Ulig's book has more detailed information regarding AL alloys; Al is not resistant to the following exposures

1. Strong acids
2. Alkalies
3. Mercury and mercury salts
4. Seawater
5. Solutions containing heavy metal ions
6. Chlorinated solvents
7. Anhydrous ethyl, propyl or butyl alcohols at elevated temperature
8. Contact with wet woods

I also checked a design handbook that I have for various seal materials. The listing for Al showed satisfactory performance in exposure to hydrogen sulphide compounds.

 

[hacksaw]

Now if I have this right you want to determine the sutability of 6061 for an actuator valve cap.

The problem I have is that such components arn't usually in contact with the process.

Can you elaborate?