To understand the corrosivity of H2S gas to metals, plastics, polymers and enamels under most ambient conditions. (E.g. moisture, temperature and volatility of substance)
Definition
H2S - Hydrogen sulfide is a colorless, flammable, extremely hazardous gas with a “rotten egg” smell. It occurs naturally in crude petroleum and natural gas, and can be produced by the breakdown of organic matter and human/animal wastes (e.g. sewage and waste water facilities).
Corrosivity to Metal (Wet Conditions)
Wet H2S is corrosive to copper, brass, bronze, cast iron, types 1010 and 1020 carbon steel, lead, Monel and 400 series stainless steels. Wet H2S is not corrosive to types 3003 and Cast B-365 aluminum, high nickel cast iron, high silicon cast iron, 300 series stainless steels, nickel-based alloys (e.g. Inconel and Incoloy) at room temperature (Up to 40°C). Wet H2S is not corrosive to Incoloy, tantalum and titanium at high temperatures (Up to 150°C).
Corrosivity to Metal (Dry Conditions)
Dry H2S is corrosive to ductile cast iron, copper, silicon-copper, aluminum bronze and silicon bronze, carbon steel. Dry H2S is not corrosive to types 1075 and 1095 carbon steel, stainless steel (types 305, 446 and Carpenter-20 Cb-3), types 3003 and 6061-T6 aluminum, nickel and nickel-based alloys at room temperature. (Up to 40°C). Dry H2S is not corrosive to types 316 and 317 stainless steels, chromium-molybdenum alloy steels, high nickel cast iron (Ni-Resist), Monel, and tantalum at high temperatures (up to 315° C).
Corrosivity to Non-Metals
Dry H2S can attack plastics, such as nylon and polyurethane. Elastomers such as Viton A,
chlorinated polyethylene, hard rubber, polyacrylate and silicone VMQ are also susceptible to
attack.
Wet H2S can attack plastics such as acetal, nylon and polyurethane. Elastomers such as Viton A, chlorinated polyethylene, natural rubber, soft rubber, isoprene, Nitrile Buna-N (NBR), styrene-butadiene (SBR), polyacrylate, polyurethane and silicone VMQ are also susceptible to attack.
Dry and Wet H2S do not attack plastics such as chlorinated polyvinyl chloride (CPVC), Teflon, Kynar (PVDF), polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), ethylene propylene, ethylene propylene diene, chloroprene, Butyl rubber (isobutyleneisoprene), Hypalon, neoprene, and ethylene vinyl acetate