Material specification page for jam nuts (thin hex, inch) 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 Jam Nuts (Thin Hex, Inch)
The highest common strength class, for high-load machine assembly. For jam nuts (thin hex, inch), 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 jam nuts (thin hex, inch) 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 Jam Nuts (Thin Hex, Inch), 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 Jam Nuts (Thin Hex, Inch) Available in Property Class 12.9 Steel
| Thread size | Across flats s (mm) | Across corners e (mm) | Nut height m (mm) | Across flats (in) | Nut height (in) | Reference standard |
|---|
