8.8 Grade – White zinc – Hexagon bolt
Grade 8.8 hexagon bolts act as the universal standard for structural engineering and heavy-duty mechanical assembly. Manufactured from medium carbon steel that has been quenched and tempered, these fasteners offer significantly higher tensile strength compared to mild steel alternatives. The white zinc plating provides a dual benefit: a clean, bright aesthetic for visible machinery and a sacrificial barrier against corrosion during storage and service.
- High Strength: Heat-treated to achieve a minimum tensile strength of 800 N/mm², making them suitable for critical load-bearing joints.
- Standard Finish: Electro-galvanized with white zinc (clear chromate) to resist oxidation in indoor or protected environments.
- Versatile Supply: Whether you need a small batch for vehicle repair or bulk pallet quantities for construction, we accommodate all order sizes.
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Why Grade 8.8 is the Industry Standard
In the fastener world, Grade 8.8 is synonymous with "structural bolt." It represents the sweet spot between high strength and ductility. Unlike mild steel (Grade 4.8), Grade 8.8 bolts are heat-treated to handle significant torque and tension without stretching permanently. This makes them the default specification for engineers designing machinery, vehicles, and steel structures where safety factors are critical.Mechanical Properties Specification
The "8.8" marking on the head is a code defined by ISO 898-1 that guarantees specific performance metrics:| Property | Value | Practical Meaning |
|---|---|---|
| Tensile Strength | 800 N/mm² (Min) | The maximum force the bolt can withstand before breaking. |
| Yield Strength | 640 N/mm² (Min) | The point where the bolt permanently stretches. 8.8 bolts can be tightened to high torque values safely. |
| Material | Medium Carbon Steel | Quenched and Tempered to achieve the required hardness. |
Quality Assurance
We supply industrial-grade fasteners. An EN 10204 3.1 Material Certificate is available upon request. Please note that third-party inspection services require an additional fee.Common Applications
Grade 8.8 white zinc bolts are versatile and found in almost every heavy industry sector:- Vehicle Assembly: Securing engines, suspension parts, and chassis components.
- Structural Steel: Indoor steel framework connections and bracing.
- Industrial Machines: Pumps, motors, and conveyor systems requiring high clamping force.
- Heavy Equipment: Earthmoving and agricultural machinery repair.