Material specification page for slotted hex nuts, unc in Property Class 12.9 Steel. Covers the grade designation (ISO 898-1 property class 12.9), corrosion and magnetic behavior, comparable grades and their trade-offs, and the sizes available to ASME B18.2.2.
Why Choose Property Class 12.9 Steel for Slotted Hex Nuts, UNC
The highest common strength class, for high-load machine assembly. For slotted hex nuts, unc, 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 slotted hex nuts, unc 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.
Comparable Grades
For Slotted Hex Nuts, UNC, 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 Slotted Hex Nuts, UNC Available in Property Class 12.9 Steel
| Size | Threads per inch | Width across flats s (in) | Nut height m (in) | T (in) | S (in) | Reference standard |
|---|---|---|---|---|---|---|
| 1/4" | 20 | 0.438 | 0.219 | 0.13 | 0.085 | ASME B18.2.2 |
| 5/16" | 18 | 0.5 | 0.266 | 0.17 | 0.105 | ASME B18.2.2 |
| 3/8" | 16 | 0.562 | 0.328 | 0.2 | 0.135 | ASME B18.2.2 |
| 7/16" | 14 | 0.688 | 0.375 | 0.22 | 0.135 | ASME B18.2.2 |
| 1/2" | 13 | 0.75 | 0.438 | 0.28 | 0.165 | ASME B18.2.2 |
| 9/16" | 12 | 0.875 | 0.484 | 0.3 | 0.165 | ASME B18.2.2 |
| 5/8" | 11 | 0.938 | 0.547 | 0.33 | 0.21 | ASME B18.2.2 |
| 3/4" | 10 | 1.125 | 0.641 | 0.39 | 0.21 | ASME B18.2.2 |
| 7/8" | 9 | 1.312 | 0.75 | 0.505 | 0.21 | ASME B18.2.2 |
| 1" | 8 | 1.5 | 0.859 | 0.575 | 0.27 | ASME B18.2.2 |
| 1 1/8" | 7 | 1.688 | 0.969 | 0.625 | 0.285 | ASME B18.2.2 |
| 1 1/4" | 7 | 1.875 | 1.062 | 0.685 | 0.355 | ASME B18.2.2 |
| 1 3/8" | 6 | 2.062 | 1.172 | 0.8 | 0.355 | ASME B18.2.2 |
| 1 1/2" | 6 | 2.25 | 1.281 | 0.84 | 0.415 | ASME B18.2.2 |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Thread, height, across-flats, property class, locking feature and flange form can all be varied, including thread sizes the standard series does not run to. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
