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 8RA Nut
| Grade |
Tensile Class |
Raw Material |
ASTM A194 Grade 8RA Chemical Components
| Grade |
Material |
UNS
Number |
C, % |
Mn, % |
Ph, % |
S, % |
Si, % |
Cr, % |
Ni, % |
Mo, % |
Ti, % |
Cb & Ta, % |
N, % |
Other Elements, % |
| 8RA |
XM19 |
S20910 |
0.060 |
4.0-6.0 |
0.045 |
0.030 |
1.000 |
20.5-23.5 |
11.5-13.5 |
1.50-3.0 |
- |
0.10-0.30 |
0.20-0.40 |
Vanadium,
0.10-0.30 |
ASTM A194 Grade 8RA Hardness Requirement
| Grade & Type |
Brinell Hardness |
Rockwell Hardness |
| C Scale |
B Scale |
| 8RA |
183-271 |
25 max |
88 min |
ASTM A194 Grade 8RA Proof Load (Inch Series)
| Nominal Size, inch |
Threads per inch |
Stress Area inch |
Proof Load, lbf |
| All Types of Grade 8 |
| Heavy Hex |
Hex |
| 1/4" |
20 |
0.0316 |
5570 |
4770 |
| 5/16" |
18 |
0.0524 |
9170 |
7860 |
| 3/8" |
16 |
0.0774 |
13560 |
11620 |
| 7/16" |
14 |
0.1063 |
18600 |
15940 |
| 1/2" |
13 |
0.1419 |
24830 |
21280 |
| 9/16" |
12 |
0.1820 |
31850 |
27300 |
| 5/8" |
11 |
0.2260 |
39550 |
33900 |
| 3/4" |
10 |
0.3340 |
58450 |
50100 |
| 7/8" |
9 |
0.4620 |
80850 |
69300 |
| 1" |
8 |
0.606 |
106000 |
90900 |
| 1 1/8" |
8 |
0.7900 |
138200 |
118500 |
| 1 1/4" |
8 |
1.0000 |
175000 |
150000 |
| 1 3/8" |
8 |
1.2330 |
215800 |
185000 |
| 1 1/2" |
8 |
1.492 |
261100 |
223800 |
ASTM A194 Grade 8RA Marking
| Grade Type |
Hot Forged or Cold Punched Nuts |
Nuts Machined from Bar Stock |