Property Class 12.9 Steel Hex Head Bolts with Reduced Shank combine the dimensional form of ISO 4015 with the material properties of grade ISO 898-1 property class 12.9: requires plating or black-oxide protection, magnetic, service range commonly limited to approx. +300 °C; confirm against the coating and the load. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose Property Class 12.9 Steel for Hex Head Bolts with Reduced Shank
The highest common strength class, for high-load machine assembly. For hex head bolts with reduced shank, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating or black-oxide protection |
Galvanic & Galling Considerations
For hex head bolts with reduced shank in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Comparable Grades
For Hex Head Bolts with Reduced Shank, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Hex Head Bolts with Reduced Shank Available in Property Class 12.9 Steel
| Size | Pitch P (mm) | b1 (mm) | b2 (mm) | c_max (mm) | d_a_max (mm) | d_s (mm) | d_w_min (mm) | Width across corners e (mm) | Head height k (mm) | k_max (mm) | k_min (mm) | k_w_min (mm) | r_min (mm) | Width across flats s (mm) | s_min (mm) | x_max (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 12 | 0 | 0.4 | 3.6 | 2.6 | 4.72 | 5.88 | 2 | 2.2 | 1.8 | 1.26 | 0.1 | 5.5 | 5.2 | 1.25 | 20~30 | ISO 4015 |
| (M3.5) | 0.6 | 13 | 0 | 0.4 | 4.1 | 3.05 | 5.22 | 6.44 | 2.4 | 2.6 | 2.2 | 1.54 | 0.1 | 6 | 5.7 | 1.5 | 20~35 | ISO 4015 |
| M4 | 0.7 | 14 | 0 | 0.4 | 4.7 | 3.5 | 6.06 | 7.5 | 2.8 | 3 | 2.6 | 1.82 | 0.2 | 7 | 6.64 | 1.75 | 20~40 | ISO 4015 |
| M5 | 0.8 | 16 | 0 | 0.5 | 5.7 | 4.4 | 7.06 | 8.63 | 3.5 | 3.74 | 3.26 | 2.28 | 0.2 | 8 | 7.64 | 2 | 25~50 | ISO 4015 |
| M6 | 1 | 18 | 0 | 0.5 | 6.8 | 5.3 | 8.74 | 10.89 | 4 | 4.24 | 3.76 | 2.63 | 0.25 | 10 | 9.64 | 2.5 | 25~60 | ISO 4015 |
| (M7) | 1 | 20 | 0 | 0.6 | 7.8 | 6.2 | 9.47 | 11.94 | 4.8 | 5.04 | 4.56 | 3.19 | 0.25 | 11 | 10.57 | 2.5 | 30~70 | ISO 4015 |
| M8 | 1.25 | 22 | 0 | 0.6 | 9.2 | 7.1 | 11.47 | 14.2 | 5.3 | 5.54 | 5.06 | 3.54 | 0.4 | 13 | 12.57 | 3.2 | 30~80 | ISO 4015 |
| M10 | 1.5 | 26 | 0 | 0.6 | 11.2 | 8.9 | 14.97 | 17.59 | 6.9 | 6.69 | 6.11 | 4.28 | 0.4 | 16 | 15.57 | 3.8 | 40~100 | ISO 4015 |
| M12 | 1.75 | 30 | 0 | 0.6 | 13.7 | 10.7 | 16.47 | 19.85 | 7.5 | 7.79 | 7.21 | 5.05 | 0.6 | 18 | 17.57 | 4.3 | 45~120 | ISO 4015 |
| (M14) | 2 | 34 | 40 | 0.6 | 15.7 | 12.5 | 19.15 | 22.78 | 8.8 | 9.09 | 8.51 | 5.96 | 0.6 | 21 | 20.16 | 5 | 50~140 | ISO 4015 |
| M16 | 2 | 38 | 44 | 0.8 | 17.7 | 14.5 | 22 | 26.17 | 10 | 10.29 | 9.71 | 6.8 | 0.6 | 24 | 23.16 | 5 | 55~150 | ISO 4015 |
| (M18) | 2.5 | 42 | 48 | 0.8 | 20.2 | 16.3 | 24.85 | 29.56 | 11.5 | 11.85 | 11.15 | 7.81 | 0.6 | 27 | 26.16 | 6.3 | 60~150 | ISO 4015 |
| M20 | 2.5 | 46 | 52 | 0.8 | 22.4 | 18.2 | 27.7 | 32.95 | 12.5 | 12.85 | 12.15 | 8.51 | 0.8 | 30 | 29.16 | 6.3 | 65~150 | ISO 4015 |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Thread size and pitch, length, property class, drive form, head geometry and head marking are all specifiable — the standard part is where it starts, not where it stops. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
