Grade 12.9 Steel Studs & Threaded Rods combine the dimensional form of DIN 939 / DIN 975 with the material properties of grade class 12.9: requires plating or black-oxide protection, magnetic, service range up to approx. +300 °C. This page summarizes the grade data, its corrosion behavior in service, the comparable grades, and the sizes supplied.
Why Choose Grade 12.9 Steel for Studs & Threaded Rods
The highest common strength class, for high-load machine assembly. For studs & threaded rods, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating or black-oxide protection |
Galvanic & Galling Considerations
For studs & threaded rods 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 Studs & Threaded Rods, 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 Studs & Threaded Rods Available in Grade 12.9 Steel
| Thread size | Pitch (mm) | Point type | Common lengths (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M4 | 0.7 | M4 | 10~100 | DIN 939 | Stud, equal thread both ends |
| M5 | 0.8 | M5 | 10~120 | DIN 939 | Stud, equal thread both ends |
| M6 | 1.0 | M6 | 12~160 | DIN 939 | Stud, equal thread both ends |
| M8 | 1.25 | M8 | 16~200 | DIN 939 | Stud, equal thread both ends |
| M10 | 1.5 | M10 | 20~250 | DIN 939 | Stud, equal thread both ends |
| M12 | 1.75 | M12 | 25~300 | DIN 939 | Stud, equal thread both ends |
| M14 | 2.0 | M14 | 30~300 | DIN 939 | Stud, equal thread both ends |
| M16 | 2.0 | M16 | 35~300 | DIN 939 | Stud, equal thread both ends |
| M18 | 2.5 | M18 | 40~300 | DIN 939 | Stud, equal thread both ends |
| M20 | 2.5 | M20 | 45~300 | DIN 939 | Stud, equal thread both ends |
| M22 | 2.5 | M22 | 50~300 | DIN 939 | Stud, equal thread both ends |
| M24 | 3.0 | M24 | 50~300 | DIN 939 | Stud, equal thread both ends |
| M27 | 3.0 | M27 | 55~300 | DIN 939 | Stud, equal thread both ends |
| M30 | 3.5 | M30 | 60~300 | DIN 939 | Stud, equal thread both ends |
| M36 | 4.0 | M36 | 70~300 | DIN 939 | Stud, equal thread both ends |
| M42 | 4.5 | M42 | 80~300 | DIN 940 | Stud, equal thread both ends |
| M48 | 5.0 | M48 | 90~300 | DIN 940 | Stud, equal thread both ends |
| M4 | 0.7 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M5 | 0.8 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M6 | 1.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M8 | 1.25 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M10 | 1.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M12 | 1.75 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M16 | 2.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M20 | 2.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M24 | 3.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M30 | 3.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |