In acidic media containing H2S, why is carbon steel resistant to H2S used instead of stainless steel?
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Dear sea friends: In acidic media containing H2S, why is carbon steel resistant to H2S used instead of stainless steel for equipment materials?
It’s possible that it’s acidic flare gas, containing H2S, along with liquid water
Chloride ions are just one factor; certain environments can cause stainless steel to become brittle. In conditions with high H2S levels and high ppm values, the corrosion rate of the passive film on stainless steel increases, leading to penetrating corrosion. Anti-H2S materials such as 08 and 09 steels are also not inexpensive, but compared to stainless steel, they still have a relatively longer service life in H2S environments.
If it’s just hydrogen sulfide, carbon steel will work. According to the corrosion data sheets, carbon steel has good resistance to hydrogen sulfide; however, 316L is even better. But when chloride ions are present, that needs to be taken into consideration, as chloride ions can cause corrosion in stainless steel. It’s important to first figure out the composition of the material
My brother analyzed it more thoroughly than I did; he’s an expert
Carbon steel is not suitable unless there is prior experience in using it
Depending on the state of the medium in use, when a liquid is present, carbon steel is better than stainless steel
To add, the reason it’s good is due to the presence of chloride ions