Stainless Steel Lock Washer

When a bolt is being used in a surface that needs protection from the pressure, washers are used to distribute the load more evenly and prevent damage. Lock washers go a step further, keeping nuts and bolts from slipping or turning once they've been installed. They can come in many styles and types, including star shapes with teeth circling the outside or as traditional washers that have uneven ends. Metric washers are no different except that their dimensions are measured and expressed within the metric system.

What Are Metric Lock Washers Used For?

Why would someone choose a lock washer over a more traditional washer, metric or otherwise? Because lock washers are helpful in securing fasteners that are exposed to vibration or other movements and effects that could loosen them over time. Using either an uneven or star-shaped lock washer, the tightening action helps prevent loosening over time due to something like vibration.

Finish

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. 316 stainless steel washers resist corrosion from wet environments as well as salt water, chlorine solutions, and chemicals.

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. Zinc-flake coated steel washers resist corrosion from chemicals and have passed a 1,000-hour salt-spray test. They’re also known as armor coat and ultra coat. Galvanized steel washers are 10 times more corrosion resistant than zinc-plated steel washers.

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

Bronze washers are corrosion resistant in wet environments, nonmagnetic, and electrically conductive.