EH36T Material

[FTBrent]

I am working on a project that will require some EH36T plate per MIL-S-22698, Class U. I understand the T denotes a Charpy test to be done. What is the Class U? I cannot find any information on this part of the material spec.

 

[BEMPE16524]

From my external source:

"Class U" refers to the material class for underwater applications. Class U plates are typically used in environments requiring high toughness and resilience, especially for structures exposed to seawater or underwater applications.

The "T" in EH36T indeed designates that the material must undergo Charpy impact testing to ensure it meets the required toughness, particularly at low temperatures, as these materials are used in challenging marine environments where impact resistance is critical.

The equivalent to MIL-S-22698 Grade EH36 (specifically with Charpy V-notch impact testing) in ASTM standards is ASTM A131 Grade EH36. ASTM A131 is the specification for structural steel plates primarily used in shipbuilding.

For underwater applications similar to those of MIL-S-22698 Class U, ASTM A131 Grade EH36 meets similar mechanical properties, chemical composition requirements, and toughness requirements. This standard also includes Charpy V-notch impact testing at specified temperatures, similar to the requirements implied by the "T" designation in EH36T.