ISO 898-2:2022 Fasteners - Mechanical properties of fasteners made of carbon steel and alloy steel – Part 2: Nuts with specified property classes
Chemical composition as per ISO 898-2:2022 for typical grades
| Class | Material and Treatment | C | Mn min. | P max. | S max. |
|---|---|---|---|---|---|
| 8 (M16 and below) | carbon steel NOT quenched and tempered (NQT) | 0.06-0.58 | 0.25 | 0.060 | 0.150 |
| 8 | carbon steel quenched and tempered (QT) | 0.15-0.58 | 0.45 | 0.048 | 0.058 |
| 10 | carbon steel quenched and tempered (QT) | 0.15-0.58 | 0.45 | 0.048 | 0.058 |
| 12 (like ISO 4032) | carbon steel quenched and tempered (QT) | 0.18-0.58 | 0.45 | 0.048 | 0.058 |
| 12 (like ISO 4033) | carbon steel quenched and tempered (QT) | 0.15-0.58 | 0.45 | 0.048 | 0.058 |
Hardness requirement as per ISO 898-2:2022 for typical grades
| Hardness scale | Size | Class 8 min. | Class 8 max. | Class 10 min. | Class 10 max. | Class 12 min. | Class 12 max. |
|---|---|---|---|---|---|---|---|
| Vickers, HV | M5 to M16 (NQT) | 200 | 334 | ||||
| Vickers, HV | M5 to M16 (QT) | 200 | 334 | 272 | 353 | 308 | 368 |
| Vickers, HV | above M16 to M39 (QT) | 233 | 334 | 272 | 353 | ||
| Vickers, HV (like ISO 4033) | M5 to M16 (QT) | 272 | 353 | ||||
| Brinell, HB or HBW | M5 to M16 (NQT) | 190 | 318 | ||||
| Brinell, HB or HBW | M5 to M16 (QT) | 195 | 195 | 268 | 349 | 304 | 363 |
| Brinell, HB or HBW | above M16 to M39 (QT) | 233 | 228 | 268 | 349 | ||
| Brinell, HB or HBW (like ISO 4033) | M5 to M16 (QT) | 268 | 349 | ||||
| Rockwell, HRC | M5 to M16 (NQT) | 33.9 | |||||
| Rockwell, HRC | M5 to M16 (QT) | 34.8 | 26.5 | 36.9 | 31.6 | 38.5 | |
| Rockwell, HRC | above M16 to M39 (QT) | 34.8 | 26.5 | 36.9 | |||
| Rockwell, HRC (like ISO 4033) | M5 to M16 (QT) | 26.5 | 36.9 |
Hardness values in Brinell and Rockwell scale for QT are converted from Vickers using ISO 18265
ISO 898-2:2012 Mechanical properties of fasteners made of carbon steel and alloy steel – Part 2: Nuts with specified property classes – Coarse thread and fine pitch thread
Chemical composition as per ISO 898-2:2012 for typical grades
| Class | Material and Treatment | C max. | Mn min. | P max. | S max. |
|---|---|---|---|---|---|
| 8 (M16 and below) | carbon steel (may be quenched and tempered) | 0.58 | 0.25 | 0.060 | 0.150 |
| 8 (above M16) | carbon steel quenched and tempered | 0.58 | 0.30 | 0.048 | 0.058 |
| 10 | carbon steel quenched and tempered | 0.58 | 0.30 | 0.048 | 0.058 |
| 12 | carbon steel quenched and tempered | 0.58 | 0.45 | 0.048 | 0.058 |
Hardness requirement as per ISO 898-2:2012 for typical grades
| Hardness scale | Size | Class 8 min. | Class 8 max. | Class 10 min. | Class 10 max. | Class 12 min. | Class 12 max. |
|---|---|---|---|---|---|---|---|
| Vickers, HV | M5 to M16 | 200 | 302 | 272 | 353 | 295 | 353 |
| Vickers, HV | above M16 to M39 | 233 | 353 | 272 | 353 | 272 | 353 |
| Brinell, HB | M5 to M16 | 190 | 287 | 259 | 336 | 280 | 336 |
| Brinell, HB | above M16 to M39 | 221 | 336 | 259 | 336 | 259 | 336 |
| Rockwell, HRC | M5 to M16 | – | 30 | 26 | 36 | 29 | 36 |
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