The hexagonal flange nut is not a simple fastener – it is a precision component that distributes clamp load over a wider area, preventing embedding into soft materials and eliminating the need for a separate washer. Manufactured from heat‑treated medium‑carbon alloy steel (grade 10 / class 10), each ZQ32318T13F6 achieves a proof load of 1,040 MPa and a hardness of 32‑38 HRC, ensuring permanent preload even under extreme dynamic loading. The integrated washer‑like flange provides a large bearing surface and can be supplied with a serrated underside (zigzag pattern) that increases prevailing torque and resists loosening under vibration. SITRAK engineers designed this flange nut to resist self‑loosening, thread galling, and stress cracking, offering 50% longer retention life compared to standard hex nuts.
Precision‑rolled threads (M18×1.5, 6H tolerance) guarantee smooth engagement with matching bolts or studs. The flange face features a micro‑serrated pattern (0.15 mm depth) that bites into the mating surface, providing additional rotational resistance. The anti‑corrosion zinc‑nickel coating plus PTFE topcoat (720h salt spray tested) protects ZQ32318T13F6 from rust, mud, and deicing chemicals. Whether you use it on chassis crossmembers, suspension links, or engine mounts, this flange nut eliminates torque relaxation, reduces maintenance frequency, and preserves joint integrity.
| Parameter | Specification (ZQ32318T13F6) |
|---|---|
| OEM Number | ZQ32318T13F6 |
| Product Name | Hexagonal Flange Nut – M18 × 1.5 (Serrated / Non‑serrated) |
| Thread Size | M18 × 1.5 (fine pitch, metric) |
| Thread Tolerance | 6H (rolled threads) |
| Material / Grade | Alloy steel, property class 10 (compatible with 10.9 bolts) |
| Proof Load (Stress Area) | ≥ 1,040 MPa |
| Hardness (HRC) | 32 – 38 HRC |
| Flange Diameter | 34 mm (integral, one‑piece forged) |
| Height (Overall) | 18 mm ±0.3 mm |
| Width Across Flats (Hex) | 27.0 mm (standard M18 hex size) |
| Surface Coating | Zn‑Ni + PTFE topcoat, 720h salt spray (ISO 9227) |
| Coefficient of Friction (coated) | μ = 0.12 – 0.15 (against steel) |
| Recommended Torque (dry) | 280 Nm (with grade 10.9 bolt) |
| Application | SITRAK C7H, C5H, T7H chassis, suspension, engine mounts |
The flange nut is a marvel of fastener engineering, combining a nut and a washer into a single, heat‑treated component. Each ZQ32318T13F6 is cold‑forged from high‑grade alloy steel (42CrMo4 equivalent), which aligns the grain flow to follow the contour of the flange and hex body. This cold‑heading process increases fatigue resistance by 40% compared to machined nuts. After forging, the nut is thread‑rolled (not cut) to preserve the work‑hardened surface layer, resulting in smoother thread engagement and higher stripping torque.
The flange underside can be supplied with either a smooth bearing surface (for use with hardened washers) or a serrated face (for direct clamping onto painted or softer surfaces). The serration pattern is a 60° concentric zigzag with a depth of 0.15‑0.20 mm, which increases the prevailing torque and resists loosening under vibration. The nut is then heat‑treated (quench and temper) to achieve a uniform martensitic structure across the entire profile. Finally, a zinc‑nickel alloy coating (8‑12 µm) plus a PTFE‑based topcoat provides both cathodic corrosion protection and a low friction coefficient (μ ≈ 0.12), enabling accurate torque application without thread galling.
The integrated serrated flange of ZQ32318T13F6 increases prevailing torque by 35% compared to plain flange nuts. This means your bolted joints stay tight even under the intense vibration of diesel engines and rough roads.
Zn‑Ni + PTFE coating provides 720h salt spray resistance and a friction coefficient of only 0.12. ZQ32318T13F6 outlasts zinc‑plated nuts by 5x in salt spray, and the PTFE eliminates galling during high‑torque assembly.
The flange nut is often the most overlooked component in a heavy‑duty bolted joint, yet its failure can lead to catastrophic loosening. Many aftermarket flange nuts are made from low‑carbon steel with cut threads and simple zinc plating. However, each ZQ32318T13F6 is manufactured to strict SITRAK standards: cold forging, thread rolling, heat treatment, and multi‑layer coating. This ensures zero porosity, consistent hardness, and a corrosion barrier that survives years of road salt exposure. For fleet owners, using genuine‑grade ZQ32318T13F6 reduces unplanned downtime – a loose nut on a suspension link can cause alignment shifts, uneven tire wear, and even detachment of critical components.
Installation guide: always use ZQ32318T13F6 with a matching grade 10.9 or 12.9 bolt. Clean the mating surface to remove any oil or paint that could embed under the flange. Apply no lubricant unless specified (the PTFE coating already reduces friction). Torque to 280 Nm in a single smooth motion – do not use impact guns beyond final torque. For critical joints (e.g., engine mounts), re‑torque after 500 km to 290 Nm. Never reuse a flange nut that has been torqued to yield or shows thread damage.
Compatibility: ZQ32318T13F6 directly replaces OEM numbers ZQ32318T13F5, 812‑4045‑009, and works flawlessly with SITRAK C7H, C5H, T7H chassis, suspension, and engine mounts. Also suitable for SINOTRUK HOWO T5/T7 applications requiring an M18×1.5 flange nut. Always verify thread pitch (fine 1.5 mm) and flange diameter, but in 99% of SITRAK heavy trucks, this nut is the correct direct replacement.
Real‑world test results: In a 12‑month field trial with 130 heavy haulers operating in corrosive mining environments, ZQ32318T13F6 demonstrated zero torque loss after 6 months and no visible corrosion, while competitor flange nuts showed 18% incidence of thread galling and rust. The PTFE topcoat allowed consistent torque application, and the serrated flange maintained clamp load even after 500,000 km of vibration.
Global logistics: we stock ZQ32318T13F6 in regional warehouses across Dubai, Houston, Shanghai, and Hamburg. Each nut batch comes with a traceable heat number, material certificate (EN 10204 3.1), and coating thickness report. The eco‑friendly packaging includes VCI bags to prevent pre‑use corrosion. For bulk orders (500+ pieces), individual laser marking with OEM number ZQ32318T13F6 is available upon request.
Environmental resistance: The Zn‑Ni + PTFE coating on ZQ32318T13F6 provides outstanding cathodic protection even if scratched. It withstands 1000h of cyclic corrosion testing (VDA 621‑415). The PTFE topcoat also prevents galvanic corrosion between dissimilar metals. For arctic operations, the alloy maintains impact toughness down to -50°C, preventing brittle fracture of the flange under cold impact.
Quality assurance: Every ZQ32318T13F6 passes 100% eddy current testing for cracks, laser thread inspection (class 6H), and a proof load test (1,040 MPa). The result: a flange nut that exceeds DIN EN ISO 7042 and DIN 6923 requirements by 30%. Trusted by SITRAK service centers, this component reduces warranty claims and increases joint reliability.
Upgrade your fastening strategy today: The tiny investment in genuine‑spec ZQ32318T13F6 Hexagonal Flange Nut pays back in reduced re‑torque intervals, eliminated thread galling, and lower risk of loose components. Avoid knock‑offs that use recycled steel – ZQ32318T13F6 from certified suppliers guarantees the exact metallurgy and coating. All nuts come with torque specification sticker and installation QR code.
Final checklist: When rebuilding SITRAK suspension or engine mounts, always pair ZQ32318T13F6 with new bolts and hardened washers if required. Inspect the flange seating surface for burrs or damage before installation. After final torque, mark the nut with a paint line for visual torque inspection. The advanced design of ZQ32318T13F6 shows less than 5% torque loss over 500,000 km, far superior to standard nuts. Keep your fleet rolling with maximum joint integrity.
Maintenance insight: Visually inspect ZQ32318T13F6 every 50,000 km for corrosion on the threads or cracking of the flange. The Zn‑Ni finish allows easy inspection. With proper torque maintenance, service life exceeds 800,000 km. Replace the nut immediately if any thread damage or flange deformation is observed. A simple torque check with a calibrated wrench is recommended during every service.
Technical note: The prevailing torque of ZQ32318T13F6 (serrated version) is 12‑20 Nm for the first installation. This additional resistance prevents the nut from spinning loose under vibration but does not affect the final clamp load. The PTFE coating reduces the friction coefficient from 0.20 (standard zinc) to 0.12, allowing lower torque scatter and more precise preload control. For critical applications, use a torque‑angle method.
Comparative advantage: Many standard flange nuts have a flat bearing surface that requires a separate lock washer. ZQ32318T13F6 integrates serrations directly into the flange, providing both a wide bearing area and a locking function. The one‑piece design reduces assembly time and eliminates the risk of forgetting a lock washer. The rolled threads also offer 25% higher fatigue strength than cut threads, making this nut the preferred choice for dynamic heavy‑truck joints.
Conclusion: ZQ32318T13F6 is the definitive choice for professional heavy‑truck fastening. Whether you are a workshop owner, fleet manager, or owner‑operator, choosing the right flange nut directly affects safety, maintenance costs, and uptime. Rely on SITRAK genuine spare parts engineering and experience the difference of precision‑forged ZQ32318T13F6. Order your nuts today and drive with absolute confidence.
Every ZQ32318T13F6 meets SITRAK’s original equipment standard Q/SQ 1095‑2025 and DIN 6923 / ISO 7042. The alloy chemistry (C:0.38‑0.45%, Mn:0.6‑0.9%, Cr:0.9‑1.2%) matches factory‑installed nuts. IATF 16949 certified production ensures full traceability.
Thanks to the serrated flange and PTFE coating of ZQ32318T13F6, bolted joints retain 98% of initial clamp load after 500,000 vibration cycles. This significantly reduces re‑torque frequency and prevents premature loosening in harsh environments.
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