Product Summary

Longze Heavy-Duty Taper Washers (DIN 434 / DIN 435) are specialized square fasteners designed to compensate for the natural slope of U-channel and I-beam flanges.

Manufactured in Yongnian, China, our taper washers ensure that the bolt head or nut sits on a perfectly level surface, preventing bending stress on the bolt shank. Whether for

heavy industrial framing, railway infrastructure, or solar mounting systems, Longze taper washers provide the structural alignment and load distribution required for high-tension bolted joints.

• ✔ Precise Flange Compensation: Our washers are forged with exact inclinations—8% for DIN 434 (U-Channels) Ve 14% for DIN 435 (I-Beams)—ensuring a 100% flush seating for the fastener.

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• ✔ Anti-Slip Grooves: Featuring parallel grooves on the sloping side, Longze washers provide mechanical friction against the beam flange, preventing the washer from shifting during high-torque tightening.

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• ✔ High-Load Distribution: The oversized square footprint distributes the clamping force over a wider area, protecting the beam's structural integrity and preventing hole deformation.

• Standards: DIN 434 (8% for U-Beams), DIN 435 (14% for I-Beams).

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• Diameter Range (d2): M8 to M30 (Custom sizes available).

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• Material Options: Carbon Steel (Q235/Q355), SS304, SS316.

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• Hardness Classes: 100HV to 200HV.

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

Mechanical Properties & Material Standards

• Matching the washer slope to the specific beam profile for maximum stability.

• Standart	Inclination	Beam Compatibility	Surface Grooves	Load Alignment
  DIN 434	8%	U-Channel (UNP)	2 Parallel Grooves	Lateral Stability
  DIN 435	14%	I-Beam (INP)	1 Central Groove	Axial Tension

Standard Cross Arm Dimensions

• Common dimensions for standard (DIN 434/435) metric taper washers.

• Thread Size (D)	Outside Size (a x b)	Thickness (h)	Hole Dia (d2)	Weight (kg/100pcs)
  M12	30 x 30 mm	4.9 mm	13.5 mm	2.50 kg
  M16	36 x 36 mm	5.9 mm	17.5 mm	4.30 kg
  M20	44 x 44 mm	7.0 mm	22.0 mm	7.50 kg
  M24	56 x 56 mm	8.5 mm	26.0 mm	14.50 kg

Surface Treatment & Environment

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

• Finish Type	Malzeme	Salt Spray Test	Appearance	Çevre
  Hot-Dip Galv.	Carbon Steel	500 - 800 Hours	Dull Grey	Outdoor / Marine
  Zinc Plated	Carbon Steel	72 - 144 Hours	Bright Silver	Indoor Structural
  Passivated	Stainless	144 - 240 Hours	Bright	Chemical / Food

Avoid Pitfalls:

• Mixing 434 and 435: Using an 8% washer on a 14% I-beam creates an uneven gap, leading to bolt fatigue. Longze clearly stamps our washers to ensure the correct inclination is used.

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• Hydrogen Embrittlement: For high-strength steel washers, we implement a strict 8 - 12 hour baking cycle after plating to prevent sudden cracking under load.

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• Rough HDG Surfaces: Poorly dipped washers can have zinc "tears." We utilize a Centrifugal Spinning process after the hot-dip bath to ensure a smooth, uniform coating.

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Perfect Fit Assembly:

• Orientation: Always place the grooved/sloping side against the beam flange and the flat side against the bolt head or nut.

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• Matching Components: We recommend pairing these with Longze DIN 931 Grade 8.8 Bolts for a complete, vibration-resistant structural assembly.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including computerized inclination angle verification, thickness gauging, and salt spray analysis.

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• Sea-Worthy Packaging: Packed in heavy-duty 25kg bags or cartons, plastic-lined, secured on reinforced pallets for export from our Yongnian hub.

Q: Why can’t I just use a standard flat washer (DIN 125) on a U-channel? A: Standard channels (UNP/INP) have a tapered flange (8% - 14% slope). If you use a flat washer,

the bolt head sits at an angle, creating a bending moment on the shank. This leads to bolt fatigue and eventual snapping. Longze Taper Washers provide a level seating surface,

ensuring the bolt only experiences pure tension.

Q: How do I distinguish between DIN 434 and DIN 435 on-site? A: Look at the Grooves (防滑槽) and the Slope:

• DIN 434 (8%): Typically has 2 parallel grooves. It is thinner at the edge and designed for U-Channels (UNP).

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• DIN 435 (14%): Typically has 1 central groove. It is significantly thicker at one end and designed for I-Beams (INP).

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• Longze Pro Tip: Every batch from our factory is stamped with the DIN number to prevent installation errors.

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Q: Does Hot-Dip Galvanizing (HDG) affect the slope accuracy? A: Standard HDG can leave "zinc pools" that ruin the 8%/14% precision. At Longze, we use Centrifugal Spinning immediately after the zinc bath. This flings off excess molten zinc, ensuring the taper remains exact and the bolt fits perfectly flush.

Q: What material grade should I choose for a Class 8.8 Bolt? A: For Class 8.8 bolts, we recommend our Medium Carbon Steel (Hardened) washers. If the washer is too soft (Low Carbon), the bolt head will "crush" into the washer under high torque, losing the pre-load. We ensure the washer hardness matches the bolt strength class.

Q: Can you manufacture custom sizes or different inclinations? A: Yes. While 8% and 14% are the global standards, some specialized solar racking or bridge projects require custom angles (e.g., 5% or 10%). Our Yongnian facility can CNC-machine custom taper washers to your exact CAD drawings.

Q: How do I prevent the washer from slipping during tightening? A: This is why our washers feature Surface Grooves. These grooves bite into the beam flange. Always ensure the sloping (grooved) side faces the beam and the flat side faces the bolt head/nut.