Standard Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or both.
ASTM A194M 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 A194M Nut Grades
Grade |
Material |
UNS
Number |
2H |
Carbon Steel |
- |
2HM |
Carbon Steel |
- |
3 |
Type 501 |
- |
4 |
Carbon, Molybdenum Steel
|
- |
6 |
Type 410 |
S41000 |
7 |
Type 4140, 4142, 4145, 4140H, 4142H, 4145H |
- |
7M |
Type 4140, 4142, 4145, 4140H, 4142H, 4145H |
- |
8 |
Type 304 |
S30400 |
8M |
Type 316 |
S31600 |
8T |
Type 321 |
S32100 |
16 |
Chromium Molybdenum Vanadium |
- |
ASTM A194M Chemical Composition
Element |
Grade 2H, 2HM |
Grade 3 |
Grade 4 |
Grade 6 |
Grade 7, 7M |
Grade 8 |
Grade 8M |
Grade 8T |
Grade 16 |
Carbon |
0.40 min |
0.10 min |
0.4-0.5 |
0.15 |
0.37-0.49 |
0.08 |
0.08 |
0.080 |
0.36 -0.47 |
Manganese |
1.00 |
1.00 |
0.7-0.9 |
1.000 |
0.65-1.10 |
2.00 |
2.00 |
2.000 |
0.45-0.70 |
Phosphorus |
0.04 |
0.04 |
0.035 |
0.04 |
0.035 |
0.045 |
0.045 |
0.045 |
0.035 |
Sulphur |
0.05 |
0.03 |
0.04 |
0.03 |
0.04 |
0.03 |
0.030 |
0.030 |
0.040 |
Silicon |
0.40 |
1.00 |
0.15-0.35 |
1.00 |
0.15-0.35 |
1.00 |
1.00 |
1.000 |
0.15-0.35 |
Chromium |
|
4.0-6.0 |
|
11.5-13.5 |
0.75-1.2 |
18-20 |
16-18 |
17.0-19.0 |
0.80-1.15 |
Nickel |
|
|
|
|
|
8-11 |
10-14 |
9.0-12.0 |
|
Molybdenum |
|
0.40-0.65 |
0.20-0.30 |
|
0.15-0.25 |
|
2.0-3.0 |
|
0.50-0.65 |
Titanium |
|
|
|
|
|
|
|
5 x (C+N),
Min – 0.70 max |
|
Nitrogen |
|
|
|
|
|
|
|
0.100 |
|
Other Elements |
|
|
|
|
|
|
|
|
Vanadium 0.25-0.35
AluminumB 0.015 |
ASTM A194M Hardness Requirement
Grade & Type |
Brinell Hardness |
Rockwell Hardness |
C Scale |
B Scale |
2H to 1-1⁄2 in. or M36, incl. |
248-327 |
24-35 |
- |
2H over 1-1⁄2 in. or M36 |
212-327 |
35 max |
95 min |
2HM and 7M |
159-235 |
- |
84 - 99 |
3, 4, 7, 16 |
248-327 |
24 - 35 |
- |
6 |
225-271 |
20-28 |
- |
8, 8C, 8M, 8T, 8F, 8MLCuN |
126-300 |
32 max |
60 min |
ASTM A194M Proof Load
Nominal Size, mm |
Threads per inch |
Stress Area, mm2 |
Proof Load, lbf |
All Grades of 8 |
Grade 2, 2HM, 6, 7M |
Grade 2H, 3, 4, 7, 16 |
Heavy hex |
Hex |
Heavy hex |
Hex |
Heavy hex |
Hex |
M6 |
1.0 |
20.1 |
11.1 |
10.4 |
20.8 |
18.7 |
29.2 |
20.8 |
M8 |
1.25 |
36.6 |
20.1 |
18.8 |
37.9 |
34.0 |
44.1 |
37.9 |
M10 |
1.50 |
58.0 |
31.9 |
29.9 |
60.0 |
53.9 |
69.9 |
60.0 |
M12 |
1.75 |
84.3 |
46.4 |
43.4 |
87.3 |
78.4 |
101.6 |
87.3 |
M14 |
2.0 |
115.0 |
63.3 |
59.2 |
119.0 |
107.0 |
138.6 |
119.0 |
M16 |
2.0 |
157.0 |
86.4 |
80.9 |
162.5 |
146.0 |
189.2 |
162.5 |
M20 |
2.5 |
245.0 |
134.8 |
126.2 |
253.6 |
227.8 |
295.2 |
253.6 |
M22 |
2.5 |
303.0 |
166.7 |
156.0 |
313.6 |
281.8 |
365.1 |
313.6 |
M24 |
3.0 |
353.0 |
194.2 |
181.8 |
365.4 |
328.3 |
425.4 |
365.4 |
M27 |
3.0 |
459.0 |
252.5 |
236.4 |
475.1 |
426.9 |
553.4 |
475.1 |
M30 |
3.5 |
561.0 |
308.6 |
288.9 |
580.6 |
521.7 |
676.0 |
580.6 |
M36 |
4.0 |
817.0 |
449.4 |
420.8 |
845.6 |
759.8 |
984.5 |
845.6 |
ASTM A194M Marking
Grade & Type |
Hot Forged or Cold Punched Nuts |
Nuts Machined from Bar Stock |
2H |
2H |
2HB |
2HM |
2HM |
2HMB |
4 |
4 |
4B |
6 |
6 |
6B |
7 |
7 |
7B |
7M |
7M |
7MB |
8 |
8 |
8B |
8M |
8M |
8MB |
8T |
8T |
8TB |
16 |
16 |
16B |