Product Summary

Longze Heavy-Duty Hex Bolts are engineered for high-load structural connections. Manufactured in Yongnian, China, we specialize in high-tensile fasteners for global infrastructure projects.

• ✔ High Strength: Grade 8.8, 10.9, and ASTM A325/A490 available.

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• ✔ Superior Coating: Hot Dip Galvanized (HDG) ≥55μm for 30+ years of rust protection.

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• ✔ Fast Response: 12-hour technical quotation and MTC support.

• Standards: DIN 933 (Full Thread), DIN 931 (Half Thread), ISO 4017, ASTM A325.

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• Diameter Range: M6 to M64 | 1/4" – 2-1/2".

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• Grade: 8.8, 10.9, 12.9 | ASTM A325 Type 1 | ASTM A193 B7.

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• Surface Finish: HDG, Zinc Plated, Dacromet, Geomet, Black Oxide.

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• Match your steel structure thickness with the correct Hex Bolt size and length for a secure assembly.

• Use this guide to select the optimal material based on your project's load and environment.

• Avoid Pitfalls:

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  • Hydrogen Embrittlement Control: Specialized baking for Grade 10.9+ fasteners after plating to prevent sudden fracture.

  • Thread Tolerance Management: Precision over-tapping for HDG nuts ensures zero seizing on site.

  • Raw Material Traceability: 100% chemical verification for every heat number.

• Perfect Fit Assembly:

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  • Complete Sets: Matching high-strength heavy hex nuts and structural washers provided.

  • Standard Compliance: Strict adherence to DIN/ISO/ASME head dimensions for perfect tooling fit.

• Extreme Condition Adaptation:

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  • High Corrosion Defense: HDG ≥55μm for marine and industrial C5-M environments.

  • Temperature Resilience: B7 and Grade 10.9 maintain structural integrity under extreme loads.

• Quality Control & Logistics:

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  • ISO 9001 Certified: 5-step QC from raw material to final dimension check.

  • Sea-Worthy Packaging: Reinforced cartons + Fumigation-Free Pallets for safe maritime transit.

• Q: Can you provide MTC (Mill Test Certificates)? A: Yes, full traceability and MTC are provided for every batch.

• Q: What is the lead time for A325 HDG bolts? A: Standard sizes are typically shipped from our Yongnian factory within 10–15 days。