Eliminate corrosion failures & costly on-site rework. Hot-dip galvanised hex countersunk bolts engineered for marine, infrastructure & heavy-equipment — delivered at factory-direct pricing with full traceability.
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⚡ Eliminate corrosion failures & costly on-site rework. Hot-dip galvanised hex countersunk bolts engineered for marine, infrastructure & heavy-equipment — delivered at factory-direct pricing with full traceability.
Standard zinc plating fails under salt spray, humidity & UV. 63% of outdoor fastener failures are corrosion-related (DataIntelo, 2025).
Improper countersink angle or weak hex drive strips under torque — causing rework, injuries & project delays.
Low-cost imports often fail spec, forcing 15–30% cost overruns in replacement labor & logistics. Supply chain disruptions add 22% more risk (DataInsights, 2025).
Oversized packaging & low packing density inflate freight. 40% higher logistics cost vs. optimised bulk supply.
You need a galvanised hex countersunk bolt that delivers 30+ years of service life, meets ASTM A153 / ISO 1461, and comes from a vertically integrated factory that controls quality from melt to finish.
Our galvanised hex countersunk bolt is manufactured on CNC automated forging lines with hot-dip galvanising (HDG) per ASTM A153 / ISO 1461. Designed for flush-mount outdoor assemblies where a smooth surface, corrosion resistance, and high torque are critical.
| Parameter | Specification | Notes |
|---|---|---|
| Material | Carbon Steel #35 / #45 / Alloy Steel 40Cr | Brinell 180–220 HB |
| Coating | Hot-Dip Galvanised (HDG) – 65–85 µm | ASTM A153 / ISO 1461 |
| Thread Standard | UNC / UNF / Metric (M6–M30) | Class 6g / 6h |
| Hex Drive Size | #3 – #6 (per ASME B18.2.1) | Recessed hex slot |
| Countersink Angle | 82° / 90° / 100° | Flat head, flush fit |
| Tensile Strength | Grade 4.8 / 8.8 / 10.9 | Up to 1,040 MPa |
| Salt Spray Resistance | ≥720 h (red rust) | Independent lab tested |
| Packing | 25 kg cartons / bulk pallets / OEM kits | Custom barcode & labelling |
30,000㎡ base, 120+ CNC machines, 500K+ pcs/month. 15 in-house engineers with decade average experience.
ISO 9001, IATF 16949-ready. 100% dimensional & hardness check. Salt spray & tensile test per batch.
Custom head marking, thread length, coating thickness. 20+ new products launched annually for niche outdoor applications.
Stock programme: 7–15 days for standard sizes. Express production in 72h for urgent orders.
CE · RoHS · FCC · CB
+ 150 Global Leaders
"We tested 6 suppliers for coastal bridge project. Their galvanised hex countersunk bolt passed 720h salt spray with zero red rust. 30% cost saving vs. European source. Now our approved vendor."
"OEM custom marking with our logo, perfect 82° countersink. Delivery 11 days ahead of schedule. The team understood our mounting rail torque spec immediately."
"We used 12,000 units for highway guardrail. Zero head pop-out, zero stripping. The hot-dip coating is uniform — no drips or uneven thickness. Highly recommend."
"35% lower landed cost than our previous supplier. The consignment arrived with full MTC and batch traceability. Exactly what we need for government projects."
Our MOQ is 2,000 pcs per size for standard stock items. For OEM custom sizes, MOQ starts at 5,000 pcs. We can also consolidate multiple sizes in one container to meet your project mix.
They meet ASTM A153 / ISO 1461 for hot-dip galvanising, ASME B18.2.1 for dimensions, and ISO 898-1 for mechanical properties. We also provide CE, RoHS, and FCC declarations upon request.
Yes. We offer free samples (up to 10 pcs) for qualified buyers. You only pay the courier cost. Samples are shipped with full test reports including salt spray and tensile data.
We ship via FOB Tianjin / Shanghai or CIF to your port. For urgent orders, we use air freight (3–5 days). We also manage customs documentation, IPPC wood packaging, and full container consolidation.
7–15 days for standard sizes in stock. 20–30 days for OEM production. We offer 72h express production for urgent breakdown orders (surcharge applies).
Absolutely. We can stamp your logo, grade, or batch code on the bolt head. Packaging options include bulk cartons, poly bags, shrink-wrapped trays, or custom kits with barcode labelling.
Our ISO 9001 QMS covers incoming raw material inspection, in-process SPC, and final inspection per ANSI/ASQ Z1.4 (AQL 0.65). Each batch includes a Certificate of Analysis (CoA) with dimensional, hardness, and coating thickness data.
With 14 years in fastener metallurgy and hot-dip galvanising, Liang leads our R&D team at Handan Guanbiao. He has overseen 200+ outdoor infrastructure projects across 28 countries and holds 3 patents in corrosion-resistant coating technology.
Limited-time: Free sample kit + full test report for first 10 qualified buyers in Q2 2026. Risk-free: If our bolts don't pass your salt spray test, we replace the entire order — no questions asked.
📧 info@topfastener.com | 📞 +86 190 3327 4954
LiuHan Township, Yongnian District, Handan, Hebei, China | www.maxfastener.com
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