When Slotted Round Nut — GB/T 812 (Series 069) are required in Grade 12.9 Steel, the alternative grades and the trade-offs between them matter as much as the dimensions. This page covers both, plus mechanical and corrosion data.
Why Choose Grade 12.9 Steel for Slotted Round Nut — GB/T 812 (Series 069)
The highest common strength class, for high-load machine assembly. For slotted round nut — gb/t 812 (series 069), 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 |
Corrosion Behavior in Service
Carbon and alloy steel slotted round nut — gb/t 812 (series 069) 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 Round Nut — GB/T 812 (Series 069), 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 Round Nut — GB/T 812 (Series 069) Available in Grade 12.9 Steel
| Size | Pitch (mm) | Outer diameter D (mm) | Nut height m (mm) | Slot width (mm) | Slot depth (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M10x1.0 | 1.0 | 18 | 8 | 3 | 2 | GB/T 812 / DIN 1804 |
| M12x1.25 | 1.25 | 22 | 8 | 3 | 2 | GB/T 812 / DIN 1804 |
| M16x1.5 | 1.5 | 28 | 8 | 4 | 2.5 | GB/T 812 / DIN 1804 |
| M20x1.5 | 1.5 | 34 | 10 | 4 | 2.5 | GB/T 812 / DIN 1804 |
| M24x1.5 | 1.5 | 40 | 10 | 5 | 3 | GB/T 812 / DIN 1804 |
| M30x1.5 | 1.5 | 48 | 12 | 5 | 3 | GB/T 812 / DIN 1804 |
| M36x1.5 | 1.5 | 58 | 12 | 6 | 3 | GB/T 812 / DIN 1804 |
| M48x1.5 | 1.5 | 72 | 15 | 6 | 4 | GB/T 812 / DIN 1804 |
| M60x2.0 | 2.0 | 90 | 18 | 7 | 4 | GB/T 812 / DIN 1804 |
| M80x2.0 | 2.0 | 115 | 20 | 8 | 5 | GB/T 812 / DIN 1804 |
| M100x2.0 | 2.0 | 140 | 22 | 10 | 5 | GB/T 812 / DIN 1804 |