washers

1. Choose Based on Load Distribution Requirements

• For general fastening: Use flat washers (DIN 125 / ISO 7089) to distribute load and protect surfaces.

• For soft materials (aluminum, wood, plastic): Choose large OD/fender washers (DIN 9021) to prevent pull-through.

• For precision assemblies: Use machined washers to maintain exact tolerances.

2. Select the Proper Anti-Loosening Function

• Vibration environments (machinery, automotive, solar mounting):
  Choose spring washers (DIN 127), split lock washers, or serrated lock washers (DIN 6798).

• High vibration or critical joints:
  Combine washers with Nyloc nuts, prevailing torque nuts, or thread-locking adhesive.

• Not recommended: Split lock washers alone for heavy-duty structures — may lose preload.

3. Choose Material Based on Working Environment

• Indoor/dry environment: Carbon steel with zinc plating is sufficient.

• Outdoor environment: Use hot-dip galvanized or Dacromet-coated washers for long-term corrosion resistance.

• Marine / high-salt / chemical exposure: Choose 316 stainless steel for maximum durability.

• Electrical or insulation applications: Use nylon, PTFE, or fiber washers.

4. Select Washer Thickness and Hardness

• For high-strength bolts (8.8 / 10.9 / 12.9):
  Use hardened washers (HV 200 / HV 300) to prevent compression damage.

• For normal bolts (4.8 / 5.8 / A2-70):
  Standard washers are sufficient.

• For structural steel connections:
  Follow DIN 6916 / EN 14399 large hardened washers.