Flat Washers

A flat disc with a centrally located hole
Provides a bearing surface thus minimizing surface wear
Distributes fastener loads evenly to minimize surface deformation (when tightening fasteners)
Conducts electricity
May cover large clearance holes
Has more compression strength and can handle higher forces than non-metallic
Aluminum 5712
Light weight — 1/3 the weight of steel
Good sealing capability
Non-magnetic
Good electrical conductor (30% copper)
Good heat conductor (70 btu/hr/sq ft/°F/ft)
May be anodized to increase corrosion resistance and is available in a wide variety of colors
Beryllium Copper 5718
Good electrical conductor (17-22% copper)
May be heat treated for higher strength
Corrosion resistant
Non-magnetic
Good heat conductor (68 btu/hr/sq ft/°F/ft)
Good vase metal for plating
Excellent spring material
Brass 5714
Good electrical conductor (26% copper)
Non-magnetic
Excellent plating base
Corrosion resistant — especially in a marine environment
Good heat conductor (70 btu/hr/sq ft/°F/ft)
Copper 5716
Excellent electrical conductor (100% copper)
Excellent sealing capability
Corrosion resistant
Good plating base
Excellent thermal conductivity (225 btu/hr/sq ft/°F/ft)
Non-magnetic
Steel 5702
Least expensive metallic washer
Good plating base
Fair electrical conductor (12% copper)
Most commonly used material
Highest strength for cost

Flat Washers

Flat Washers & Nuts Bolt