Metric Bolt Mechanical Strength
Printable shop wall chart: Metric Bolt Mechanical Strength. Free letter-size PDF to print and post at the counter; 25 x 36 inch poster version available.
| Class | Tensile Rm (min) | Yield (min) | Proof stress | Hardness (HV) | Matching nut |
|---|---|---|---|---|---|
| 4.6 | 400 MPa | 240 MPa | 225 MPa | 120 - 220 | 5 |
| 4.8 | 420 MPa | 340 MPa | 310 MPa | 130 - 220 | 5 |
| 5.8 | 520 MPa | 420 MPa | 380 MPa | 160 - 220 | 5 |
| 8.8 (to M16) | 800 MPa | 640 MPa | 580 MPa | 250 - 320 | 8 |
| 8.8 (over M16) | 830 MPa | 660 MPa | 600 MPa | 255 - 335 | 8 |
| 9.8 (to M16) | 900 MPa | 720 MPa | 650 MPa | 290 - 360 | 9 |
| 10.9 | 1040 MPa | 940 MPa | 830 MPa | 320 - 380 | 10 |
| 12.9 | 1220 MPa | 1100 MPa | 970 MPa | 385 - 435 | 12 |
Nut classes per ISO 898-2. 12.9 is most common on socket head cap screws. Verify against the current edition of ISO 898-1.
These tables carry the same figures as the printed sheet below.
The printed sheet
25 x 36 inch poster version
For the full-size shop poster, tell us where to send it.
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Text version of this sheet
4.6
8.8
10.9
CLASS 4.6
CLASS 8.8
CLASS 10.9
12.9
12.9 (TYP. SOCKET)
ISO 898-1 minimum mechanical properties by property class
Class
Tensile Rm (min)
Yield (min)
Proof stress
Hardness (HV)
Matching nut
4.6
400 MPa
240 MPa
225 MPa
120 - 220
5
4.8
420 MPa
340 MPa
310 MPa
130 - 220
5
5.8
520 MPa
420 MPa
380 MPa
160 - 220
5
8.8 (to M16)
800 MPa
640 MPa
580 MPa
250 - 320
8
8.8 (over M16)
830 MPa
660 MPa
600 MPa
255 - 335
8
9.8 (to M16)
900 MPa
720 MPa
650 MPa
290 - 360
9
10.9
1040 MPa
940 MPa
830 MPa
320 - 380
10
12.9
1220 MPa
1100 MPa
970 MPa
385 - 435
12
Nut classes per ISO 898-2. 12.9 is most common on socket head cap screws. Verify against the current edition of ISO 898-1.
The Fastener App | TheFastenerApp.com
Fastener Guide reference FG-044A76 · thefastenerapp.com/fastener-guide/wall-charts/metric-bolt-mechanical-strength · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
