Phosphate Coating
Phosphate coating (phosphatizing) applied per ASTM F1137 to carbon steel fasteners. Provides a crystalline conversion coating that enhances paint adhesion, reduces friction during assembly, and offers moderate corrosion resistance. Available in zinc phosphate and manganese phosphate grades, with or without oil supplementary treatment.
| Standard | ASTM F1137 |
| Base Material | Carbon Steel, Alloy Steel |
| Salt Spray | 24–96 hours (oiled finish) |
| Thickness | 2–25 µm |
| Applications | Automotive, flanged joints, torque-critical assemblies, paint adhesion base |
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Phosphate coating is a chemical conversion process in which the fastener surface reacts with a phosphoric acid solution to form an integral, crystalline phosphate layer. Asia Bolts Industries applies phosphate coatings per ASTM F1137, which covers both zinc phosphate and manganese phosphate grades for threaded fasteners.
Unlike electroplated coatings, phosphate does not add significant dimensional build-up — making it ideal for precision-threaded fasteners where tight tolerance control is critical. The coating is typically 2–25 µm thick and is porous, which allows it to retain supplementary rust-preventive oils (oiled finish) for enhanced protection, or to serve as a paint/primer adhesion promoter.
Phosphate Grade Options:
• Zinc Phosphate: Fine-grained, excellent paint adhesion, lower friction — preferred for bolts requiring torque-tension control
• Manganese Phosphate: Coarser grain, high oil retention, better wear resistance — preferred for heavy-duty mechanical fasteners
Grade Classification per ASTM F1137:
• Grade 1: Zinc phosphate without supplemental oil
• Grade 2: Zinc phosphate with supplemental oil
• Grade 3: Manganese phosphate without supplemental oil
• Grade 4: Manganese phosphate with supplemental oil
• Grade 5: Zinc phosphate with dry film lubricant
Common applications include automotive fasteners, flange bolts, heavy structural bolts, and bolts used in flanged joint assemblies where controlled torque-tension is required. All phosphate coated fasteners from Asia Bolts are supplied with coating type, weight, and oil supplement documentation.
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Packaging Information
📦 Standard: Cartons, wooden boxes or pallets based on quantity and customer requirements
🎁 Custom: Polybag + carton on request
🚢 Export: Fumigated pallets available
📋 Each box includes inspection certificate
Delivery Information
📦 Lead Time: Stock items: 1-5 days | Custom manufacturing: 7-30 days
🚢 Shipping Methods: Air freight, sea freight, or land transportation. FOB, CIF, DDP terms available.
📋 Full export documentation provided with every shipment: Commercial Invoice, Packing List, MTC, Bill of Lading, and Certificate of Origin
☑ Saudi Aramco Approved: Recognized vendor for critical upstream and downstream projects.
🔩 Custom Manufacturing: We produce non-standard lengths and diameters based on your drawings.
🏅 Triple ISO + CE Certified: ISO 9001 Quality, ISO 45001 Safety, and ISO 14001 Environmental certification, plus CE marking for European market compliance.
🏭 32,260 sqm Facility: The largest fastener manufacturing complex in the Middle East, equipped with advanced CNC machinery and full in-house production capability.
🔬 In-House Testing Lab: Full material traceability from raw stock to finished product. Tensile, hardness, dimensional, and spectroscopic testing all performed on-site.
🚚 Global Delivery: Shipped to 70+ countries via established logistics networks. Flexible packaging, documentation and third-party inspection support available.
