Carbon Steel Zinc Plated Grade 8.8 Hexagon Flange Bolt
Product Overview
Grade 8.8 hexagon flange bolts are high-strength carbon steel fasteners equipped with an integrated flange under the head, providing a larger bearing surface that distributes load evenly. With a galvanized surface finish, these bolts offer moderate corrosion resistance and are ideal for applications requiring both secure tightening and improved clamping force. The combination of strength, ease of installation, and anti-loosening performance makes them a popular choice in automotive, mechanical, and structural assemblies.
Product Specification Table
| Specification | Detail |
|---|---|
| Product Name | Grade 8.8 Hexagon Flange Bolt |
| Material | Carbon Steel |
| Strength Grade | 8.8 |
| Surface Finish | Zinc Plated (Galvanized) |
| Head Type | Hexagon with Integrated Flange |
| Thread Type | Metric / UNC |
| Standards | ISO 4162 / DIN 6921 / JIS B1189 |
| Size Range | M5–M20, 1/4″–1″ |
| Length Range | 10mm–150mm |
Technical Parameters
| Mechanical Property | Value |
|---|---|
| Tensile Strength | ≥800 MPa |
| Yield Strength | ≥640 MPa |
| Hardness | 23–34 HRC |
| Proof Load | 85% of minimum tensile strength |
| Coating Thickness | ≥5 µm (Zinc) |
| Salt Spray Resistance | 72–96 hours (standard zinc finish) |
Material Introduction & Production Process
These flange bolts are made of medium carbon steel, heat-treated to achieve the mechanical properties required for grade 8.8. The zinc plating provides a protective layer that delays rust and enhances the bolt’s appearance.
Production Steps:
Raw carbon steel bar selection and inspection
Cold heading and forging of hex head with flange
Thread rolling for precision threading
Heat treatment (quenching and tempering)
Zinc electroplating
Dimensional inspection and mechanical testing
This controlled process ensures structural integrity and tight manufacturing tolerances for safe and reliable performance.
Typical Applications & Industry Use
Grade 8.8 hexagon flange bolts are widely used in:
Automotive engines, chassis, and suspension systems
Agricultural equipment and trailers
Steel structures and metal frame assembly
Heavy machinery and power transmission systems
Railway components and rail fastening systems
The built-in flange eliminates the need for separate washers, offering time savings during assembly.
Product Advantages & Competitive Features
High Strength Flange Bolts for Secure and Efficient Assembly
Flybear delivers precision-engineered Grade 8.8 flange bolts that combine mechanical performance with cost-efficiency.
High-Quality Carbon Steel: Meets strength class 8.8 requirements for structural load-bearing
Precision Threading: Ensures consistent fit and torque control
Zinc Coating for Rust Resistance: Provides basic corrosion protection in indoor or semi-exposed environments
Washer-Free Design: Flange design reduces installation time and increases clamping reliability
Flexible Supply: Custom lengths, thread styles, and bulk packaging options available
Full Support: Engineering and logistics team ensures technical compatibility and fast delivery
Company Testing & Quality Control
At Flybear Fastener, quality is monitored throughout every production stage with a dedicated QA team performing:
Material verification through spectrometer analysis
Dimensional inspection with calibrated gauges
Coating adhesion and thickness checks
Hardness and tensile strength testing
Compliance with ISO 898-1 and DIN 6921 standards
Selection & Procurement Guidelines
When choosing Grade 8.8 hexagon flange bolts, consider the following:
Required tensile and shear strength
Environmental exposure and appropriate coating
Thread type and assembly torque
Whether flange design offers advantages over traditional bolts + washers
We welcome OEM requirements and project-specific inquiries. Drawings and custom specifications are accepted for production.
Conclusion & Company Promotion
We always uphold the philosophy of “quality first, customer foremost,” and are committed to providing customers with high-quality fastener products and one-stop fastening solutions.
To learn more or explore our full product range, please contact us for expert advice and competitive quotes.
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