Swing Bolt manufactured in A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) are dimensioned to GB/T 77 / ISO 4026. 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 A2 Stainless Steel for Swing Bolt — GB/T 77 / ISO 4026 (Series 020)
The most common stainless group for indoor and general outdoor fasteners. For swing bolt — gb/t 77 / iso 4026 (series 020), this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Good general corrosion resistance |
Corrosion Behavior in Service
A2 (304) gives excellent atmospheric and most-water corrosion resistance and is the most common stainless for Swing Bolt — GB/T 77 / ISO 4026 (Series 020) in indoor and general outdoor service. In chloride-bearing environments (marine air, road salt, swimming pools) consider stepping up to A4 (316).
Comparable Grades
For Swing Bolt — GB/T 77 / ISO 4026 (Series 020), the alternative stainless grade is A4 (316). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Swing Bolt — GB/T 77 / ISO 4026 (Series 020) Available in A2 Stainless 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 |
