Product Overview
Hot-dip Galvanized Bolts with Hex Head, Grade 8.8, made in China, are designed for demanding environments. Available in sizes M8 to M33 (5/16″ to 1-1/4″), these bolts feature a thick galvanized coating for superior corrosion resistance and durability. Ideal for construction and industrial use, they pair perfectly with hot-dip galvanized nuts for secure connections.
Technical Specifications
| Execution Standard | ISO 4014 / GB 5782 |
| Material | Medium Carbon Steel (C 0.25-0.55%, Mn 0.6-1.2%) |
| Surface Treatment | Hot-Dip Galvanizing (Average Film Thickness ≥50μm) |
| Strength Grade | Grade 8.8 (Tensile Strength ≥800MPa) |
| Thread Specification | Metric Coarse Thread (M6-M36) |
| Corrosion Resistance | 1000-hour Neutral Salt Spray Test |
| Mechanical Properties | Hardness HRC22-32 |
| Torque Coefficient | 0.18-0.22 (Galvanized Surface) |
| Available Sizes | M8×20 to M33×130 (Multiple lengths available for each diameter) |
Hot-Dip Galvanized Bolts Size Chart
| Metric (Metric) | Length (mm) | Imperial (Imperial) | Length (inches) |
|---|---|---|---|
| M8 | 20, 25, 30 | 5/16″ | 0.79″, 1.00″, 1.18″ |
| M10 | 20, 25, 30, 35 | 3/8″ | 0.79″, 1.00″, 1.18″, 1.38″ |
| M12 | 25, 30, 35, 40 | 1/2″ | 1.00″, 1.18″, 1.38″, 1.57″ |
| M14 | 30, 35, 40 | 9/16″ | 1.18″, 1.38″, 1.57″ |
| M16 | 30, 35, 40 | 5/8″ | 1.97″, 2.36″, 2.76″, 3.22″ |
| M18 | 50, 60, 70 | 7/8″ | 2.76″, 3.15″, 3.54″ |
| M20 | 40, 45, 50, 55 | 1″ | 1.57″, 1.77″, 1.97″, 2.17″ |
| M22 | 70, 80, 90, 100 | 1-1/16″ | 2.76″, 3.15″, 3.54″, 3.94″ |
| M24 | 50, 60, 70, 75 | 15/16″ | 1.97″, 2.36″, 2.76″, 2.95″ |
| M27 | 70, 80, 90 | 1-1/16″ | 2.76″, 3.15″, 3.54″ |
| M30 | 70, 80, 90 | 1-1/8″ | 2.76″, 3.15″, 3.54″ |
| M33 | 110, 120, 130 | 1-1/4″ | 4.33″, 4.72″, 5.12″ |
Key Notes:
- Corrosion Resistance: Hot-dip galvanized coating provides excellent corrosion protection, suitable for harsh environments.
- Variety of Sizes: Available in sizes from M8 to M33, with lengths ranging from 20mm to 130mm.
- High Strength: Thicker zinc coating enhances bolt durability and load-bearing capacity.
- Wide Applications: Ideal for use in construction, machinery, bridges, and high-humidity environments.
- Metric/Imperial Conversion: Complete metric and imperial size chart to meet global market demands.
- Cost-effective & Eco-friendly: Long-lasting protection, reducing maintenance costs, and complying with environmental standards.
- Stable Supply: Ensures stable delivery for bulk orders, suitable for long-term partnerships.
Application Scenarios
Hot-dip Galvanized Bolts are perfect for construction, machinery, and outdoor infrastructure. They are commonly used in steel structures, bridges, factories, highways, power poles, and marine applications. Their corrosion resistance ensures secure, long-lasting performance in harsh environments:
Construction Projects
Essential for construction projects requiring strong and corrosion-resistant fasteners in tropical and coastal environments
Outdoor Structures
Perfect for outdoor structures exposed to harsh weather conditions or coastal environments with high salt content
Heavy Machinery Assembly
Used in heavy machinery assembly and industrial equipment requiring long-term reliability and strength
Infrastructure Projects
Critical for infrastructure such as bridges, railways, power plants, and transmission towers requiring durability
Automotive and Marine
Automotive and marine applications needing durable bolts with superior anti-rust properties in challenging environments
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 is the main advantage of hot-dip galvanized bolts?
Hot-dip galvanizing provides a thick, durable zinc coating (≥50μm) that protects bolts from corrosion, extending their service life especially in outdoor or humid environments. This process offers superior protection compared to electroplating, making it ideal for Southeast Asia’s tropical climate.
Are these bolts suitable for marine or coastal use?
Yes, the hot-dip galvanized finish offers excellent resistance to saltwater corrosion, making them highly suitable for marine and coastal applications. They pass 1000-hour salt spray tests, ensuring long-term performance in harsh coastal environments.
What does Grade 8.8 mean?
Grade 8.8 refers to the bolt’s high tensile strength (800 MPa minimum) and yield strength ratio. It indicates a high-strength bolt commonly used in demanding structural applications where reliability and load-bearing capacity are critical.
Can I use these bolts for heavy machinery assembly?
Absolutely, their Grade 8.8 strength and superior corrosion resistance make them ideal for machinery where reliability is critical. The hot-dip galvanized coating also provides long-term protection in industrial environments with exposure to moisture and chemicals.
How to ensure proper installation of these bolts?
Use the correct torque as specified in installation guides (considering the 0.18-0.22 torque coefficient for galvanized surfaces), and ensure washers or locking mechanisms are used when necessary to maintain bolt integrity. Proper installation ensures optimal performance and longevity.
Contact Us
Need more information about our Hot-Dip Galvanized Hex Head Bolts or have special requirements? Our technical sales team is ready to serve customers across Southeast Asia with customized corrosion-resistant fastener solutions.
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