Product Overview
Our Hot-Dip Galvanized Hex Head Bolts are high-strength corrosion-resistant fasteners manufactured according to ISO 4014/GB 5782 standards, crafted from premium carbon steel with hot-dip galvanizing treatment, achieving Grade 8.8 strength classification (tensile strength ≥800MPa). Available in both full-thread and partial-thread designs to meet different connection requirements, the hot-dip galvanized coating provides superior corrosion protection (salt spray test ≥1000 hours), making these bolts the preferred fastening solution for power transmission towers, marine engineering, outdoor steel structures, and other demanding environments across Southeast Asia.
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) |
Application Scenarios
These Hot-Dip Galvanized Hex Head Bolts are widely used across Southeast Asia in critical applications requiring exceptional strength and corrosion resistance:
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
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.
Our Manufacturing Facility and Products
Direct Supply from Chinese Factory
Welcome to Handan Quanfan Metal Products Co., Ltd., a leading China manufacturer specializing in fasteners including self drilling screws, drywall screws, stainless steel bolts, self tapping screws, and grade 5 nuts.
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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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