Hex Nuts manufactured in Property Class 8.8 Steel (ISO 898-1 property class 8.8) are dimensioned to ISO 4032 / ISO 4033. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Property Class 8.8 Steel for Hex Nuts
The workhorse medium-carbon alloy class for structural joints. For hex nuts, 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 hex nuts 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 Hex Nuts, class 10.9 or 12.9 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 Hex Nuts Available in Property Class 8.8 Steel
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Nut height m style 1 (mm) | Nut height m style 2 (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M1 | 0.25 | 2.5 | 2.71 | 0.8 | - | Below the ISO 4032 range (M1.6-M64); manufacturer series |
| M1.2 | 0.25 | 3.0 | 3.28 | 1.0 | - | Below the ISO 4032 range (M1.6-M64); manufacturer series |
| M1.4 | 0.3 | 3.0 | 3.28 | 1.2 | - | Below the ISO 4032 range (M1.6-M64); manufacturer series |
| M1.6 | 0.35 | 3.2 | 3.48 | 1.3 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M2 | 0.4 | 4.0 | 4.32 | 1.6 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M2.5 | 0.45 | 5.0 | 5.45 | 2.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M3 | 0.5 | 5.5 | 6.01 | 2.4 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M3.5 | 0.6 | 6.0 | 6.58 | 2.8 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M4 | 0.7 | 7.0 | 7.66 | 3.2 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M5 | 0.8 | 8.0 | 8.79 | 4.7 | 5.1 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M6 | 1.0 | 10.0 | 11.05 | 5.2 | 5.7 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M8 | 1.25 | 13.0 | 14.38 | 6.8 | 7.5 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M10 | 1.5 | 16.0 | 17.77 | 8.4 | 9.3 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M12 | 1.75 | 18.0 | 20.03 | 10.8 | 12.0 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M14 | 2.0 | 21.0 | 23.36 | 12.8 | 14.1 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M16 | 2.0 | 24.0 | 26.75 | 14.8 | 16.4 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M18 | 2.5 | 27.0 | 29.56 | 15.8 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M20 | 2.5 | 30.0 | 32.95 | 18.0 | 20.3 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M22 | 2.5 | 34.0 | 37.29 | 19.4 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M24 | 3.0 | 36.0 | 39.55 | 21.5 | 23.9 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M27 | 3.0 | 41.0 | 45.2 | 23.8 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M30 | 3.5 | 46.0 | 50.85 | 25.6 | 28.6 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M33 | 3.5 | 50.0 | 55.37 | 28.7 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M36 | 4.0 | 55.0 | 60.79 | 31.0 | 34.7 | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M39 | 4.0 | 60.0 | 66.44 | 33.4 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M42 | 4.5 | 65.0 | 71.3 | 34.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M45 | 4.5 | 70.0 | 76.95 | 36.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M48 | 5.0 | 75.0 | 82.6 | 38.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M52 | 5.0 | 80.0 | 88.25 | 42.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
| M56 | 5.5 | 85.0 | 93.56 | 45.0 | - | ISO 4032 (Style1) / ISO 4033 (Style2, M5-M36 preferred sizes) |
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. 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.
