A 2H nut has a medium strength. Its primary uses are for pressure valves and vessels, pipelines, pressure controls, chemical, gasoline, and oil storage systems, natural gas and steam storage, and transmission of chemicals, gasoline, oil, steam, and natural gas.
Basically it’s best for high temperature applications and high-pressure conditions because it’s designed to withstand extreme environment conditions.
A 2H Nut should not be confused with a 2HM Nut. Although they have the same chemical composition, the manner they are tested are different. The former requires only a small sample to be tested while the latter needs the whole population to undergo testing.
The hardness requirements and the proof load between the two also differ. The 2H Nut has a Brinell Hardness minimum of 147 (depending on the size) while the 2HM’s is 159. The proof load of a ½ in. 2H and 2HM are 24, 830 and 21,800, respectively.
1/2, 5/8, 3/4, 7/8, 1, 1-1/8
1-1/4, 1-3/8, 1-1/2, 1-3/4, 2