Product Summary

Longze High-Strength Hex Flange Nuts (DIN 6923 / ISO 4161) are high-performance fasteners featuring an integrated wide flange that acts as a fixed, non-spinning washer.

Manufactured in Yongnian, China, our flange nuts are designed to distribute clamping pressure over a larger surface area and bridge oversized or irregular holes. Whether for solar

mounting structures, automotive exhaust systems, or heavy machinery assembly, Longze flange nuts (also known as Whiz Nuts) provide the structural stability and anti-vibration security required for critical joints.

• ✔ Integrated Washer Design: The broad flange base eliminates the need for separate flat washers, reducing assembly time and inventory complexity by 50%.

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• ✔ Superior Anti-Loosening: Our serrated flange option (Whiz Nut) features precision-engineered teeth that "bite" into the mating surface, providing high resistance to vibration-induced loosening.

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• ✔ High-Tensile Reliability: Precision-forged and heat-treated to meet Property Class 8 and 10 requirements, ensuring the internal threads will not strip even under extreme torque.

• Standards: DIN 6923, ISO 4161, EN 1661, ASME B18.16.4.

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• Thread Range: M3 to M20 | 1/4" to 3/4".

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• Property Class: Class 8, 10, 12 | Stainless Steel 304 (A2) & 316 (A4).

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• Flange Type: Serrated (Anti-vibration) or Smooth (Surface protection).

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• Surface Finish: Zinc Plated (Clear/Yellow), Hot Dip Galvanized (HDG), Black Oxide, Dacromet.

Mechanical Properties & Material Standards

• Matching the steel grade to the structural requirements of the transmission line.

• Property Class	Matériel	Proof Load Stress (min)	Hardness Range	Best Application
  Class 8	Medium Carbon Steel	800 - 855 MPa	180 - 302 HV	Solar Racking / Framing
  Class 10	Acier allié	1040 - 1060 MPa	272 - 353 HV	Automotive Chassis
  SS304 (A2)	Acier inoxydable	700 MPa	200 - 280 HV	Food Grade / Outdoor
  SS316 (A4)	Acier inoxydable	800 MPa	240 - 320 HV	Marine / Coastal

Standard Cross Arm Dimensions

• Common angle steel configurations for standard utility pole mounting.

• Thread Size (D)	Flange Dia (dc)	Total Height (m)	Width Across Flats (s)	Pitch (Metric)
  M6	14.2 mm	6.0 mm	10 mm	1.0 mm
  M8	17.9 mm	8.0 mm	13 mm	1.25 mm
  M10	21.8 mm	10.0 mm	15 mm	1.5 mm
  M12	26.0 mm	12.0 mm	18 mm	1.75 mm

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Surface Treatment	Coating Thickness	Salt Spray Test	Best Environment	Appearance
  Zinc Plated	8 - 12 μm	72 - 144 Hours	Indoor Machinery	Clear / Yellow
  Hot Dip Galv.	≥ 45 μm	500 - 800 Hours	Outdoor Infrastructure	Dull Grey
  Dacromet	8 - 12 μm	500 - 1000 Hours	Automotive / Marine	Silver Grey
  Zinc-Nickel	8 - 10 μm	1000+ Hours	Coastal / EV Battery	Matte Grey

Avoid Pitfalls:

• Serration Depth: If the "Whiz" teeth are too shallow, they won't lock. Longze utilizes high-precision molds to ensure every serration is sharp enough to resist rotation but optimized to prevent excessive surface damage.

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• Flange Eccentricity: A flange that isn't perfectly centered causes uneven load distribution. We use multi-station cold-heading machines to ensure 100% concentricity between the hex and the flange.

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• Hydrogen Embrittlement (Class 10): For Class 10 electroplated nuts, we perform an immediate 4-8 hour baking process to eliminate hydrogen, preventing sudden brittle failure under load.

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Perfect Fit Assembly:

• Matched Flange Bolts: Pair these with our Longze DIN 6921 Flange Bolts for a unified fastening system that maximizes contact area and minimizes the risk of loosening.

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• Smooth vs. Serrated: Utiliser Smooth Flange Nuts for painted or delicate surfaces to avoid scratching, and Écrous à embase dentelée for high-vibration structural joints.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including computerized optical sorting for thread integrity, Proof Load testing, and salt spray analysis.

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• Sea-Worthy Packaging: Packed in heavy-duty 25kg cartons, plastic-lined for moisture protection, and secured on reinforced pallets for maritime export from our Yongnian facility.

• Q: Can you provide oversized tapping for HDG nuts? A: Yes, for Hot Dip Galvanized applications, we tap nuts to 6AZ (Oversized) to ensure they spin freely onto HDG bolts without compromising the zinc protection.

• Q: Do you offer fine-pitch flange nuts? A: Absolutely. We stock M10x1.25 and M12x1.25 Class 10 flange nuts, which are widely used in the automotive and motorcycle industries.