Product Summary

Longze Precision Tubular Rivets (DIN 7340) are high-efficiency hollow fasteners designed for lightweight structural joining and electrical feed-through applications. Manufactured

in Yongnian, China, our tubular rivets are cold-drawn to ensure consistent wall thickness and a smooth internal bore. Whether for securing friction linings, assembling multi-layer

PCB components, or reinforcing leather-to-metal joints, Longze hollow rivets provide a secure, low-profile bond that allows for internal passage of wires or secondary fasteners.

• ✔ Consistent Wall Uniformity: Our precision drawing process ensures the tube wall thickness is uniform within ±0.03mm, preventing lopsided deformation or splitting during the flaring (rolling) process.

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• ✔ Optimized Ductility (Soft Annealed): Every batch of brass and aluminum rivets is fully annealed to ensure maximum malleability, allowing the tail to form a perfect, crack-free 360° roll-over.

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• ✔ Seamless Internal Bore: The smooth, burr-free internal diameter is ideal for electrical applications where wires must pass through the rivet without the risk of insulation abrasion.

• Standards: DIN 7340 (Form A, B, C), ISO Equivalent.

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• Diameter Range (d1): 1.0 mm to 16.0 mm.

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• Length Range: 2.0 mm to 100 mm.

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• Material Options: Brass (CuZn37), Aluminum (5052), Stainless Steel (304), Copper.

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• Head Style: Flat Round (Form A) / Rolled Edge.

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• Surface Finish: Nickel Plated, Tin Plated (for soldering), Passivated, Plain.

Mechanical Properties & Material Standards

• Matching the rivet material to the conductivity and structural needs of the assembly.

• Material Type	Graad	Electrical Conductivity	Ductility	Best Application
  Brass	CuZn37	High	Excellent	Electrical / Terminals
  Aluminium	5052	Moderate	High	Lightweight Signs / Toys
  Stainless 304	A2	Low	Moderate	Medical / Food Grade
  Copper	C1100	Extreme	Excellent	Power Transformers

Standard Cross Arm Dimensions

• Common dimensions for standard (DIN 7340 Form A) metric tubular rivets.

• Outside Dia (d1)	Inside Dia (d2)	Head Dia (d3)	Wall Thickness (s)	Head Height (k)
  2.0 mm	1.6 mm	3.2 mm	0.20 mm	0.3 mm
  3.0 mm	2.5 mm	4.8 mm	0.25 mm	0.5 mm
  4.0 mm	3.4 mm	6.4 mm	0.30 mm	0.6 mm
  5.0 mm	4.3 mm	8.0 mm	0.35 mm	0.8 mm

Surface Treatment & Soldering Compatibility

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

• Finish Type	Materiaal	Salt Spray Test	Appearance	Advantage
  Tin Plated	Brass / Copper	48 - 72 Hours	Matte Silver	Excellent Soldering
  Nickel Plated	Brass	72 - 120 Hours	Shiny Silver	Wear Resistance
  Anodized	Aluminium	240+ Hours	Clear / Colors	Aesthetic / Marine
  Passivated	Stainless	144 - 240 Hours	Bright	Chemical Resistance

Avoid Pitfalls:

• Wall "Splitting": If the rivet material is too hard or the wall is too thin, the tail will split like a star during flaring. Longze utilizes Vacuum Annealing to ensure the metal remains soft enough for a smooth roll.

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• Inaccurate Hole Sizing: A hollow rivet requires a precise fit. If the hole is too large, the tube will buckle internally before the head forms. We recommend a hole clearance of no more than +0.1mm over the outside diameter (d1).

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• Length Calculation Error: For a standard roll-over, the rivet length should be Total Material Thickness + (0.5 to 0.7) x d1. Using too much length leads to a messy, unstable clinch.

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Perfect Fit Assembly:

• Flaring Tools: Always use a polished, hardened steel flaring punch (Squeezer) to ensure the rolled edge is uniform and aesthetic.

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• Electrical Conductivity: For grounding or terminal applications, use our Tin-Plated Brass rivets to ensure low contact resistance and easy PCB soldering.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including computerized wall thickness gauging, flaring test (to check for cracks), and material conductivity verification.

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• Sea-Worthy Packaging: Packed in small moisture-proof polybags, then secured in reinforced 25kg master cartons to prevent crushing or oxidation during export from our Yongnian hub.

• Q: Can you provide "Eyelet" style rivets for very thin materials? A: Yes, we manufacture ultra-thin wall eyelets for the textile and electronic industries with custom flange diameters.

• Q: Do you offer semi-tubular rivets (where only the tip is hollow)? A: Yes, we produce both DIN 7340 (Full Tubular) en Semi-Tubular rivets for applications requiring higher shear strength in the middle of the joint.