When Swing Bolt — GB/T 77 / ISO 4026 (Series 020) are required in Grade 8.8 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 8.8 Steel for Swing Bolt — GB/T 77 / ISO 4026 (Series 020)
The workhorse medium-carbon alloy grade for structural joints. For swing bolt — gb/t 77 / iso 4026 (series 020), 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 swing bolt — gb/t 77 / iso 4026 (series 020) 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 swing bolt — gb/t 77 / iso 4026 (series 020) 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 Swing Bolt — GB/T 77 / ISO 4026 (Series 020) Available in Grade 8.8 Steel
| Thread size | Pitch (mm) | Ring outer dia D (mm) | Ring wire dia (mm) | Total length L (mm) | SWL (kg, axial) | Reference standard |
|---|---|---|---|---|---|---|
| M8 | 1.25 | 20 | 8 | 36 | 140 | DIN 580 / GB/T 825 |
| M10 | 1.5 | 25 | 10 | 45 | 230 | DIN 580 / GB/T 825 |
| M12 | 1.75 | 30 | 12 | 54 | 340 | DIN 580 / GB/T 825 |
| M16 | 2.0 | 35 | 14 | 63 | 700 | DIN 580 / GB/T 825 |
| M20 | 2.5 | 40 | 16 | 72 | 1200 | DIN 580 / GB/T 825 |
| M24 | 3.0 | 50 | 20 | 90 | 1800 | DIN 580 / GB/T 825 |
| M30 | 3.5 | 60 | 25 | 108 | 3200 | DIN 580 / GB/T 825 |
| M36 | 4.0 | 72 | 30 | 126 | 5000 | DIN 580 / GB/T 825 |