Product Overview
Our Grade 8.8 Bolts are high-strength fasteners made to ISO 898-1 standards from premium carbon steel with a black oxide finish. These bolts meet Grade 8.8 strength (tensile strength ≥800MPa) and come in full-thread and partial-thread designs for varied connection needs. The black oxide coating offers rust protection and a clean look.As dependable Stainless Steel Hex Bolts and Hex Bolts, they are ideal for mechanical equipment, engineering structures, and heavy-duty uses. Sourced directly from a reliable China factory, our bolts deliver quality and value.We export to multiple regions including the Middle East, Southeast Asia, Africa, and Central Asia, providing consistent quality and on-time delivery for global industrial customers.
Technical Specifications
| Execution Standard | ISO 898-1 |
| Material | Medium Carbon Steel (C 0.25-0.55%) |
| Surface Treatment | Black Oxide |
| Strength Grade | Grade 8.8 (Tensile Strength ≥800MPa) |
| Thread Specification | Metric Thread (M6-M24) |
| Head Type | Hex Head (Standard Across Flats) |
| Mechanical Properties | Hardness HRC22-32 |
| Corrosion Resistance | 24-hour Salt Spray Test |
| Available Sizes | Metric: M6×12–M24×50 (various lengths) Imperial: 1/4″×0.47″–15/16″×1.97″ (various lengths) |
Application Scenarios
These Grade 8.8 High-Strength Bolts are widely used across Southeast Asia in critical applications requiring superior strength and reliability:
Heavy Machinery
Essential for secure assembly of machines that require high load capacity and vibration resistance in industrial environments
Automotive Industry
Used in vehicle manufacturing and repair for critical parts including engine components, chassis, and suspension systems
Construction Projects
Fastening steel structures, bridges, and frameworks requiring high tensile strength and structural integrity
Industrial Equipment
Suitable for equipment requiring strong, durable bolts in manufacturing plants and processing facilities
Infrastructure Projects
Used in tunnels, railways, power plants, and other critical infrastructure requiring long-term reliability
Product Quality Certificate
Quality Certification Standards
Product quality is our priority, validated by Hebei Provincial Fastener Product Quality Supervision and Inspection Center. This authoritative provincial institution has rigorously tested our screws, nuts and bolts for material, hardness, strength, precision and corrosion resistance—all meeting or exceeding industry standards. This certification guarantees reliable performance for your projects.
Product Packaging Specifications
Comprehensive Packaging Solutions
- Inner Packaging: 25kg per woven bag or small box, PE bag lining
- Outer Packaging: 900kg wooden pallets or fumigated plywood cases
- Custom Packaging: Logo boxes, barcode stickers available on request
Manufacturing Facility Overview
Advanced Manufacturing Facility
Our 5,000㎡ workshop features clear zones for raw materials, processing, testing and finished goods. Equipped with over 50 advanced CNC machines and cold headers, we achieve ±0.01mm precision from wire to finished fasteners. 20+ skilled staff monitor production, while a dedicated lab with tensile testers and spectrometers ensures strict quality checks—rejecting all substandard products.
Customer Service Policy
Return & Exchange Policy
We stand behind our high-quality fasteners. For defective products, returns are accepted within 7 days of receipt (unused, in original packaging, with defect evidence); we refund product cost (shipping non-refundable). Exchanges for wrong specs or minor defects (unused) are allowed within 7 days, with customer covering shipping. Not accepted: customer-caused errors, used/damaged products, requests after 7 days.
Frequently Asked Questions
What does Grade 8.8 mean?
Grade 8.8 bolts have high tensile strength of 800 MPa minimum, making them suitable for demanding structural and mechanical applications. The first digit (8) represents tensile strength in hundreds of MPa, while the second digit (8) indicates the yield strength ratio.
How does black oxide treatment help?
Black oxide provides mild corrosion resistance and a smooth, professional surface finish. It reduces friction during installation and offers better appearance compared to plain steel, while being cost-effective for indoor and dry environments.
Can I order custom lengths?
Yes, we offer various standard sizes from M6×12 to M24×50, and can customize lengths to fit your specific project requirements. Contact our technical team for custom sizing options and minimum order quantities.
Are these bolts compatible with standard nuts?
Yes, they fit standard metric nuts designed for Grade 8.8 bolts. We recommend using matching Grade 8 nuts to ensure optimal performance and safety in high-stress applications.
What’s the difference between full-thread and partial-thread bolts?
Full-thread bolts have threads along the entire length, providing maximum holding power. Partial-thread bolts have a smooth shank section, offering better shear strength and are ideal for applications where the bolt passes through clearance holes.
Contact Us
Need more information about our Grade 8.8 High-Strength Bolts or have special requirements? We have proudly served numerous customers worldwide, including key markets in the Middle East, Southeast Asia, and Africa, delivering expert fastener solutions tailored to their needs.
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