Dear RotatingEng11,

It seems to be a typing mistake.

Normally, carbon steel is not used for HP Steam piping. ASTM A335 Gr P22 is generally used.

Regards.

DHURJATI SEN
Kolkata, India

Quote (Dhurjati Sen)

It seems to be a typing mistake.

Normally, carbon steel is not used for HP Steam piping. ASTM A335 Gr P22 is generally used.

Depends on your definition of high pressure. I do not agree.

Review a copy of the ASTM A-333 Gr 6 specification. Compare the allowable stresses in ASME II part D across the temperature spectrum with other common carbon steel piping grades like ASTM A-106-B. I've seen projects use ASTM A-333 Gr 6 (impact tested carbon steel) in applications that were not low temperature. Those who work in the project world may be better able to explain why.

Define HP.
We currently use A106B (which essentially is the same as A333-6) for piping design of the HP steam system in one of the demo plants were building, if I’m not mistaken it’s around 45 barg @ 260 deg C.

Before I retired in 2015, I saw numerous heats of A-106 B made with both fine and coarse grain melting and having Mn contents below 0.50%. If that is still the case, I would recommend A333-6, which had been made (hopefully still made) with more consistent and closer controls on chemistry, for temperatures up to 750F. If the purchaser puts greater controls on chemistry and melting practice, I would recommend A-106 B or C from temps between 650F and 750F.