DIN 432 External tab washers (locking tab washers) DIN 432 - 1983

About Washers

Types of Washers

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Flat washers are primarily used to displace the load of a fastener head or a nut on a threaded joint. They can cover holes and act as spacers.

Lock washers resist vibration to prevent a threaded joint from loosening.

Cushioning washers protect joints and dampen vibration.

Sealing washers prevent fluids from leaking around connectors.

Countersunk washers give flat and oval head screws a neat, finished appearance.

Sleeve washers act as a barrier around fasteners to block electrical current and prevent corrosion from mating different material.

Square-neck bolt washers have teeth to dig into soft material to prevent rotation.

Leveling and wave washers compensate for tolerance variations and uneven surfaces.

Washers for blind rivets are also known as backup washers and are for use with blind rivets for extra support when fastening into soft material.

Notched washers have indentations for temporarily securing them with nails to keep them from rotating during installation. They have large ODs to prevent screws from sinking into wood surfaces.

Curved washers are designed to fit round surfaces such as tubes and pipe.

Slotted washers allow you to install and remove them without completely disassembling your joints.

Washers for tie-down straps have bent sides that are good for holding and aligning tie-down straps.

Washers for electrical terminals prevent wires under screw heads from slipping out so electrical connections stay intact.

Washers for foam insulation and plaster are used to repair foam insulation and sagging, cracked plaster.

Clipped washers fit where standard flat washers can't and won't rotate when you position the flat edge against a surface.

Comparing Washer Materials and Coatings

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The addition of a finish increases the corrosion resistance of the materials shown above.

Black Oxide—This finish gives mild corrosion resistance in dry environments.

Zinc and Zinc Yellow-Chromate Plated—These finishes provide corrosion resistance in wet environments.

Hot-Dipped Galvanized—This finish has 10 times more corrosion resistance than zinc and zinc yellow-chromate platings.

Cadmium Plated—This finish resists corrosion from salt water.

Passivated—This finish adds another level of corrosion resistance to stainless steel.

Zinc-Aluminum Coated—Also known as armor coat and ultra coat, this coating resists corrosion from chemicals and passes the 1,000-hour salt-spray test.

Black Ultra-Corrosion-Resistant Coated—This durable semigloss coating resists corrosion from acids and chemicals and passes the 1,000-hour salt-spray test.