Corrosion resistance issue-----Hydrogen fluoride
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What materials can resist corrosion by fluorides (hydrogen fluoride)? Operating temperature: 300°C. What hardness is required for such materials? At 300°C, a hardness of over HRC 50 is needed – is there any material that meets this requirement? Alternatively, the hardness of the material can be increased through surface treatment.
Hastelloy; other materials don’t seem to work. Ordinary steel is sufficient if there is no water or gas present
It can only be metallic materials or inorganic non-metallic materials.
Well, non-metals do not meet this requirement.
Hastelloy B, tantalum is definitely an option
Pipelines containing hydrogen fluoride gas at temperatures over 200 degrees generally require the use of Hastelloy, Monel alloy, or Incoloy 600, among other materials
Monselloy is generally sufficient below the normal pressure boiling point; if nitric acid is present, a Hastelloy with a higher nickel content should be used
Non-metals are acceptable at this temperature and even higher, but they cannot withstand a hardness of HRC50; it is recommended to use high-nickel alloys such as Inconel 600 or C-276
In an atmosphere free of moisture, at temperatures below 160°C, SS304 is sufficient; above 160°C, 16MnR can be used. However, the flow velocity inside the pipes should be kept below 10 m/s； Anhydrous liquid phase: carbon steel is generally sufficient at room temperature
There’s something wrong with the way this question is phrased. What are the operating conditions? What is the state of HF, and what is its concentration? Are there any other fluorides present? What’s the use? All of this affects material selection. Everything has been clearly explained upstairs. Basically, there are only a few types of steel materials that can resist HF corrosion: Monel alloy, INCONEL 600, Hastelloy 276, and other high-nickel alloys. However, one characteristic of these high-nickel alloys is that they do not have high hardness. From what I’ve checked, the hardness of Hastelloy 276 is below HB250, while that of Monel alloy rods ranges from HB190 to 350. The hardness level of HRC50 that you are requesting is equivalent to HB480, which is a very high level of hardness. It is very likely that the hardness value you provided is incorrect; otherwise, it will be impossible to find a metal material that is resistant to HF corrosion while also meeting the required hardness standards.
Pure hydrogen fluoride can be handled with 316L; Hastelloy is not necessary if that’s not a concern