Also known as conical washers, these have a slightly cupped shape that gives them spring-like flexibility to grip tighter than split and tooth lock washers. They minimize loosening from wear, temperature changes, and vibration. Load-rated Belleville disc springs are also available.

18-8 stainless steel and 17-7 PH stainless steel washers have good chemical resistance and may be mildly magnetic. Zinc-plated steel washers have an outer layer of zinc that protects the inner steel from rust in wet environments and extends the life of the washer.

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The arched shape of these washers presses up against a bolt and down against a nut to prevent loosening from wear, vibration, or temperature changes. Similar to a spring, they flatten out as pressure is applied, helping to absorb shocks. They grip bolts more tightly than split and tooth lock washers. Unlike split lock washers, which can only be tightened in one direction, these washers have a continuous body that can rotate in either direction.

Conical and curved washers are functionally the same, and are often referenced using their DIN specifications. These DIN specifications refer to slight differences in OD and thickness. DIN 6796 is the standard for conical spring lock washers, which are also known as Belleville washers.

Steel washers are stronger and more wear resistant than zinc-plated steel and stainless steel. They are best for dry environments, since moisture will cause them to rust. Zinc-plated washers have an outer layer of zinc that protects the inner steel from rust and extends the life of the washer. Similar to zinc plating, washers with a black phosphate coating are protected from rust in wet environments. They have a black finish that blends in with dark surfaces.

Stainless steel washers are more corrosion resistant than steel, and almost as strong. 18-8 stainless steel washers will hold up in wet and humid environments, but will corrode if exposed to salt water or chemicals. 316 stainless steel washers are the most corrosion resistant, and will not corrode from water, salt, or chemicals.

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As a screw is tightened, these metric washers flatten to add tension to the joint, counteracting fatigue around the joint from small amounts of vibration. This makes them a common choice to prevent fasteners from loosening. However, they resist the least amount of vibration compared to other locking washers. They meet a DIN or ASME standard for split lock washer dimensions.

Curved and wave split lock washers can be used with fasteners that have right- or left-hand threads to prevent clockwise and counterclockwise rotation. These washers are reusable—they retain their shape when untightened and will not damage fasteners. Wave washers touch fasteners at more points, so they grip tighter than curved washers. Their shape also compensates for uneven surfaces and tolerance variations.

Stainless steel washers resist corrosion better than steel and are nearly as strong. 18-8 stainless steel washers withstand humid, damp, and washdown environments but will corrode when exposed to salt water and other chlorine solutions.

Stronger and more durable than stainless steel, steel washers plated with zinc or galvanized withstand varying degrees of corrosion. Zinc-plated steel and zinc yellow-chromate plated steel washers withstand wet environments. However, they will corrode in salt water and chlorine solutions. The zinc plating temporarily protects against rust, but once it wears off, the steel will rust.

Steel washers are stronger and resist wear better than zinc-plated steel and stainless steel washers. Use them in dry environments. Black-oxide steel washers have a black residue that forms from being heat treated; the color will wear away over time.

For technical drawings and 3-D models, click on a part number.