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Chapter 6
Steel Fasteners
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HARDNESS REQUIREMENTS
OF STEEL NUTS FOR HIGH-PRESSURE & HIGH-TEMPERATURE SERVICE
|
ASTM A 194 |
|
Completed Nuts |
|
Sample Nutsa |
|
Grade |
HB |
HRC |
HRB |
HB min |
HRB min |
| 1 |
121 min |
--- |
70 min |
121 |
70 |
| 2 |
159-352 |
--- |
84 min |
159 |
84 |
| 2H |
|
|
|
|
|
| To 1
1/2" (38.1 mm0 |
248-352 |
24-38 |
--- |
179 |
89 |
| Over
1 1/2 " (38.1 mm) |
212-352 |
38 max |
95 min |
147 |
79 |
| 2HM,
7M |
159-237 |
22 max |
--- |
159 |
84 |
| 3, 4,
7 |
248-352 |
24-38 |
--- |
201 |
94 |
| 6, 6F |
228-271 |
20-28 |
--- |
--- |
--- |
| 8,
8C, 8M, 8T, 8F, 8P, 8N |
126-300 |
--- |
60-105 |
--- |
--- |
| 8MN,
8LN, 8MLN, 8MLCuN |
126-300 |
--- |
60-105 |
--- |
--- |
| 8A,
8CA, 8MA, 8TA |
126-192 |
--- |
60-90 |
--- |
--- |
| 8FA,
8PA, 8NA, 8MNA |
126-192 |
--- |
60-90 |
--- |
--- |
| 8LMNA,
8MLNA, 8MLCuNa |
126-192 |
--- |
60-90 |
--- |
--- |
| 8R,
8RA, 8S, 8SA |
183-271 |
88 HRB-25 HRC |
--- |
--- |
--- |
| a.
Sample nuts require a specific heat treatment prior to testing, see ASTM A
194. |
| HB
- Hardness Brinell; HRC - Hardness Rockwell C Scale; HRB - Hardness Rockwell
B Scale. |
| |
|