Property Class 8.8 Steel Imperial Hex Nuts (UNC / UNF) are supplied to ANSI/ASME B18.2.2 / BS 1768. The grade provides requires plating (zinc) for corrosion 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 8.8 Steel for Imperial Hex Nuts (UNC / UNF)
The workhorse medium-carbon alloy class for structural joints. For imperial hex nuts (unc / unf), this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Corrosion Behavior in Service
Carbon and alloy steel imperial hex nuts (unc / unf) 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 imperial hex nuts (unc / unf) 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 Imperial Hex Nuts (UNC / UNF) Available in Property Class 8.8 Steel
| Nominal size | Thread series | Material options | Finish options |
|---|---|---|---|
| 1/4 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized |
| 5/16 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized |
| 3/8 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized |
| 1/2 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / yellow zinc / hot-dip galvanized |
| 5/8 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / hot-dip galvanized |
| 3/4 in | UNC or UNF | carbon steel or A2/A4 stainless | black oxide / blue-white zinc / hot-dip galvanized |
Dimensions are independent of the material: every size above is available in Property Class 8.8 Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
Grade 8 8 Steel is one of the grades the catalog describes. Height and across-flats are the two most often changed — a thinner nut for clearance, a larger hex for a tool that is already on the line. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
