Slotted Hex Bolt manufactured in Grade 8.8 Steel (class 8.8) are dimensioned to GB/T 5782 / ISO 4014. 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 Grade 8.8 Steel for Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005)
The workhorse medium-carbon alloy grade for structural joints. For slotted hex bolt — gb/t 5782 / iso 4014 (series 005), this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | class 8.8 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | up to approx. +300 °C |
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
Corrosion Behavior in Service
Carbon and alloy steel slotted hex bolt — gb/t 5782 / iso 4014 (series 005) 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 Bolt — GB/T 5782 / ISO 4014 (Series 005), 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 Slotted Hex Bolt — GB/T 5782 / ISO 4014 (Series 005) Available in Grade 8.8 Steel
| Size | Pitch (mm) | Nominal diameter d (mm) | Length L (mm) | Width across flats s (mm) | Width across corners e (mm) | Head height k (mm) |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 3 | 20 | 5.5 | 6.01 | 2.0 |
| M4 | 0.7 | 4 | 25 | 7.0 | 7.66 | 2.8 |
| M5 | 0.8 | 5 | 30 | 8.0 | 8.79 | 3.5 |
| M6 | 1.0 | 6 | 40 | 10.0 | 11.05 | 4.0 |
| M8 | 1.25 | 8 | 50 | 13.0 | 14.38 | 5.3 |
| M10 | 1.5 | 10 | 60 | 16.0 | 17.77 | 6.4 |
| M12 | 1.75 | 12 | 80 | 18.0 | 20.03 | 7.5 |
| M14 | 2.0 | 14 | 80 | 21.0 | 23.36 | 8.8 |
| M16 | 2.0 | 16 | 100 | 24.0 | 26.75 | 10.0 |
| M18 | 2.5 | 18 | 100 | 27.0 | 30.14 | 11.5 |
| M20 | 2.5 | 20 | 120 | 30.0 | 33.53 | 12.5 |
| M24 | 3.0 | 24 | 150 | 36.0 | 39.98 | 15.0 |
| M30 | 3.5 | 30 | 180 | 46.0 | 50.85 | 18.7 |
| M36 | 4.0 | 36 | 200 | 55.0 | 60.79 | 22.5 |