API 5L-B for sour service

[dursosono]

Refer to NACE MR0175-2003 Table D-2, material API 5L Grade A & B, Grade X-42 through X-65 have been accepted for sour service
But I don't find the limitation value of H2S partial pressure in both of API Spec 5L and NACE MR0175.

Can anyone explain this limitation?

 

[strider6]

I suggest you to use the new NACE / ISO 15156 part 2.
Regarding the H2S limit, there are no limits in terms of partial pressure of H2S for carbon steel.
there are limit for the hardness.
S

Corrosion Prevention & Corrosion Control

 

[0707]

for gasoil services, above .01 Mol % of H2S and at temperatures above 396ºC you begin to have higher and higher corrosion rates for the carbon steels

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