Partial H2S on Carbon steel

[OSaenz]

NACE MR0175 gives partial H2S limits on Stainless Steels,(i.e. 17-4 0,5psi) but is there anything that denotes a partial H2S limits for carbon steels? We use API6A DD & EE material classifications on H2S equipment, but I would like to add the H2S partial pressures to it.

 

[TVP]

What specific grades of carbon steel? How are they processed, heat treated, etc.? Susceptibility to H₂S depends a great deal on microstructure and strength/hardness.

 

[SJones]

Not quite sure what you are trying to do but have you not looked at ISO 15156 Part 2, Figure 1? There isn't the same approach to carbon steels as there is to CRAs. It's either Region 0, 1, 2, or 3.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[OSaenz]

The material meets 15156-2 A.2 for regions 0-3. Basically 4140 75k yeild, etc. I knew about figure 1, but I wasn;t sure if there were any other restrictions like there are for stainless.

 

[rconner]

I wonder if "4140" (if that is what is being talked about here?) should be referred to as a "low alloy" steel or a high-strength, "low alloy" steel, as opposed to what most people think of when they hear the term "carbon steel"?