Standard Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or both.
ASTM A194 specification covers a variety of carbon, alloy, and martensitic stainless steel nuts in the size range 1/4 through 4
in. and metric M6 through M100 nominal. It also covers austenitic stainless steel nuts in the size range 1/4 in. and M6
nominal and above. These nuts are intended for high-pressure or high-temperature service, or both.
ASTM A194 Grade 2HM Nut Grades
| Grade |
Tensile Class |
Raw Material |
ASTM A194 Grade 2HM Chemical Components
| Grade |
Material |
UNS
Number |
C, % |
Mn, % |
Ph, % |
S, % |
Si, % |
Cr, % |
Ni, % |
Mo, % |
Ti, % |
Cb & Ta, % |
N, % |
Other Elements, % |
| 2, 2HM, & 2H |
Carbon |
|
0.40 min |
1.000 |
0.040 |
0.050 |
0.400 |
- |
- |
- |
- |
- |
- |
- |
ASTM A194 Grade 2HM Hardness Requirement
| Grade & Type |
Brinell Hardness |
Rockwell Hardness |
| C Scale |
B Scale |
| 2HM |
159-235 |
- |
84 - 99 |
ASTM A194 Grade 2HM Proof Load (Inch Series)
| Nominal Size, inch |
Threads per inch |
Stress Area inch |
Proof Load, lbf |
| GRADE 2HM |
| Heavy Hex |
Hex |
| 1/4" |
20 |
0.0316 |
4130 |
3820 |
| 5/16" |
18 |
0.0524 |
6810 |
6290 |
| 3/8" |
16 |
0.0774 |
10080 |
9300 |
| 7/16" |
14 |
0.1063 |
13820 |
12760 |
| 1/2" |
13 |
0.1419 |
18450 |
17030 |
| 9/16" |
12 |
0.1820 |
23660 |
21840 |
| 5/8" |
11 |
0.2260 |
29380 |
27120 |
| 3/4" |
10 |
0.3340 |
43420 |
40080 |
| 7/8" |
9 |
0.4620 |
60060 |
55440 |
| 1" |
8 |
0.606 |
78780 |
72720 |
| 1 1/8" |
8 |
0.7900 |
102700 |
94800 |
| 1 1/4" |
8 |
1.0000 |
130000 |
120000 |
| 1 3/8" |
8 |
1.2330 |
160200 |
148000 |
| 1 1/2" |
8 |
1.492 |
194000 |
170040 |
ASTM A194 Grade 2HM Marking
| Grade Type |
Hot Forged or Cold Punched Nuts |
Nuts Machined from Bar Stock |
| 2HM |
2HM |
2HMB |