Property Class 12.9 Steel Plow Bolts (Countersunk, Square Neck) are supplied to ASME B18.9. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is commonly limited to approx. +300 °C; confirm against the coating and the load. Property data, grade comparison and the full size table follow.
Why Choose Property Class 12.9 Steel for Plow Bolts (Countersunk, Square Neck)
The highest common strength class, for high-load machine assembly. For plow bolts (countersunk, square neck), 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 |
Corrosion Behavior in Service
Carbon and alloy steel plow bolts (countersunk, square neck) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Galvanic & Galling Considerations
For plow bolts (countersunk, square neck) 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.
Sizes of Plow Bolts (Countersunk, Square Neck) Available in Property Class 12.9 Steel
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Countersink angle | Square neck width (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M10 | 1.5 | 25.4 | 6.4 | 80 | 10.5 | 25~80 | ASME B18.9 |
| M12 | 1.75 | 31.8 | 7.9 | 80 | 12.5 | 30~100 | ASME B18.9 |
| M14 | 2.0 | 35.0 | 8.7 | 80 | 14.5 | 35~110 | ASME B18.9 |
| M16 | 2.0 | 38.1 | 9.5 | 80 | 16.5 | 40~130 | ASME B18.9 |
| M20 | 2.5 | 47.6 | 11.9 | 80 | 20.5 | 50~160 | ASME B18.9 |
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. Dimensions, material, finish and form are specified from the drawing — a bolt outside the standard range is a variation on existing tooling rather than a new design. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
