Product Summary

Longze High-Strength Hex Nuts (DIN 934 / ISO 4032) are precision-engineered to provide maximum stripping resistance and clamping force when paired with high-tensile bolts.

Manufactured in Yongnian, China, our nuts are cold-forged or hot-forged depending on size, followed by controlled heat treatment to achieve Property Class 8, 10, and 12

mechanical standards. Whether for heavy-duty structural steel, automotive engines, or industrial piping, Longze hex nuts ensure a secure, fail-safe connection under extreme tension.

• ✔ Guaranteed Proof Load: Every batch is tested to ensure the internal threads can withstand the full proof load of the matching bolt grade without stripping or deforming.

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• ✔ Precision Threading: Tapped to 6H or 7H tolerances to ensure a smooth, consistent fit even after heavy-duty surface treatments like Hot Dip Galvanizing.

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• ✔ Chamfered Finish: Dual-sided chamfering (Form B) allows for easier alignment and faster assembly on automated production lines.

• Standards: DIN 934, ISO 4032, ISO 4033 (High Nuts), ASME B18.2.2.

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• Diameter Range: M3 to M100 (Metric) | 1/4" to 4" (Imperial).

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• Property Class: Class 6, 8, 10, 12 | Stainless Steel A2-70 & A4-80.

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• Thread Pitch: Coarse Thread (Standard), Fine Thread (1.0, 1.25, 1.5 pitch).

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

Mechanical Properties & Material Standards

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

• Property Class	Matching Bolt Grade	Proof Load Stress (min)	Material	Hardness Range
  Class 8	Grade 8.8	800 - 855 MPa	Medium Carbon	180 - 302 HV
  Class 10	Grade 10.9	1040 - 1060 MPa	Alloy Steel	272 - 353 HV
  Class 12	Grade 12.9	1140 - 1200 MPa	Alloy Steel	327 - 373 HV
  SS316 (A4-80)	A4-80 Bolt	800 MPa	Stainless 316	240 - 320 HV

Standard Cross Arm Dimensions

• Common angle steel configurations for standard utility pole mounting.

• Thread Size (D)	Pitch (Coarse)	Height (m)	Width Across Flats (s)	Weight (kg/1000pcs)
  M12	1.75 mm	10 mm	18 mm	15.40 kg
  M16	2.0 mm	13 mm	24 mm	30.80 kg
  M20	2.5 mm	16 mm	30 mm	60.40 kg
  M24	3.0 mm	19 mm	36 mm	103.00 kg

Galvanizing & Corrosion Resistance

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

• Surface Treatment	Process	Salt Spray Test	Best Application	Thread Fit
  Zinc Plated	Electrolytic	72 - 144 Hours	Indoor Machinery	6H (Standard)
  Hot Dip Galv.	Thermal Bath	500 - 800 Hours	Outdoor Power Grids	6AZ (Oversized)
  Dacromet	Zinc-Flake	500 - 1000 Hours	Automotive / High-Temp	6H (Precision)
  PTFE Coating	Fluoropolymer	1000 - 2000 Hours	Offshore Oil & Gas	6H/7H

Avoid Pitfalls:

• Grade Mismatching: Never use a Class 6 nut on a Grade 10.9 bolt. Longze provides clearly stamped nuts (8, 10, or 12) to prevent dangerous onsite errors that lead to joint failure.

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• Hydrogen Embrittlement (Class 10/12): For high-strength electroplated nuts, we implement a strict de-embrittlement baking process to ensure the internal threads don't become brittle and snap under load.

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• Nut Seizing (Stainless Steel): To prevent "galling" during high-speed installation of SS304/316 nuts, Longze offers specialized anti-seize lubricants or wax coatings upon request.

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Perfect Fit Assembly:

• Oversized Tapping for HDG: For hot-dip galvanized applications, we tap nuts "Oversized" (6AZ) to accommodate the 50-80μm zinc layer on the bolt, ensuring a perfect fit without compromising the thread's shear strength.

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• Fine Pitch Availability: We specialize in fine-thread nuts (e.g., M10x1.25, M24x2.0) for automotive and hydraulic applications requiring higher adjustment precision.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including hardness testing, Proof Load verification using a 300-ton hydraulic press, and thread gauge inspection.

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• Sea-Worthy Packaging: Nuts are packed in heavy-duty 25kg double-walled bags or cartons, plastic-lined for moisture protection, and palletized for secure international shipping.

• Q: Why are your HDG nuts slightly looser on a plain bolt? A: This is intentional. HDG nuts are tapped oversized to fit HDG bolts. If used on a plain bolt, the clearance will be larger, but the structural integrity is maintained once tightened.

• Q: Do you offer ISO 4032 (Newer Standard) instead of DIN 934? A: Yes. ISO 4032 nuts are slightly higher than DIN 934, providing better stripping resistance. We stock both to meet different engineering preferences.