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ISO 898-1 Grade 12.9
The Grade 12.9 Bolts, screws, and studs with specified property classes - coarse thread and fine pitch thread
The ISO 898-1:2013 Grade 12.9 specification covers carbon steel bolts and studs ranging from M-6 to M-64 diameter. We use high carbon steel material and high alloy steel raw materials to achieve the required properties of grade 12.9 . There are three popular grades in this standard, 8.8, 10.9 and 12.9 which denote material hardness strength and their respective mechanical properties.
| 12.9 |  |
Socket head cap screws, Allen bolts |
|
Property class |
Material and heat treatment |
Chemical composition limit (cast analysis, %)a |
Tempering temperature ⁰C Min. |
||||
|
C |
P |
S |
Bb |
||||
|
min. |
max. |
max. |
max. |
max. |
|||
|
12.9f h i |
Alloy steel quenched and temperedg |
0,30 |
0,50 |
0,025 |
0,025 |
0,003 |
425 |
|
12.9f h i |
Carbon steel with additives (e.g. Boron or Mn or Cr or Molybdenum) quenched and tempered |
0,28 |
0,50 |
0,025 |
0,025 |
0,003 |
380 |
|
Mechanical or physical property |
Tensile strength, Rm, MPa |
Stress at 0,2 % non-proportional elongation, Rp0,2, MPa |
Stress under proof load, Spf, MPa |
Proof strength ratio Sp,nom/ReL,min |
Percentage elongation after fracture for machined test pieces, A, % |
Percentage reduction of area after fracture for machined test pieces, Z, % |
Height of non-decarburized thread zone, E, mm |
Depth of complete decarburization in the thread, G, mm |
Reduction of hardness after retempering, HV</p> |
Impact strength, KVij, J |
||
|
nom.c |
min. |
nom.c |
min. |
nom. |
min |
min. |
min. |
min. |
max. |
max. |
min. |
|
|
12.9 |
1 200 |
1220 |
1080 |
1100 |
970 |
0,88 |
8 |
44 |
3/4 H1 |
0,018 |
23 |
k |
|
Mechanical or physical property |
Vickers hardness, HV F ≥98 N |
Brinell hardness, HBW F = 30 D2 |
Rockwell hardness, HRC |
Surface hardness, HV 0,3 |
|||
|
min. |
max. |
min. |
max. |
min. |
max. |
max. |
|
|
12.9 |
385 |
435 |
380 |
429 |
39 |
44 |
435 |