Types Of Flat Washers

Ordinary Metal Flat Washer
This is the most common type, usually made of low-carbon steel (such as ST12, Q235), medium-carbon steel (such as 45 steel, 65Mn), or stamped stainless steel. It is mainly used to increase the contact area, distribute pressure, and prevent the surface of fasteners from being scratched. It is often used in conjunction with spring washers, with the flat washer closely fitting the surface of the connected part and the spring washer placed between the flat washer and the nut.

Chamfered Flat Washer
To avoid interference with the fillet under the bolt head, some flat washers have a chamfered inner hole. This design ensures that the washer fits closely with the bolt head during assembly, prevents "turning along" issues, and improves assembly reliability and torque transmission efficiency.

Metal Flat Gasket (Industrial Sealing Type)
Unlike ordinary flat washers, these gaskets are designed for high-pressure, high-temperature, or corrosive environments and are commonly used for sealing connections in industrial equipment such as pressure vessels, valves, and flanges. Materials include aluminum, copper, and stainless steel, withstanding pressures up to 20 MPa and temperatures from -200°C to 650°C.
Basic Flat Washer Type: Made from a single metal sheet, suitable for raised face flanges.
Composite Structure Type: Includes metal-jacketed gaskets (metal and non-metal strips wound alternately) and coated types (non-metal core covered with a metal layer), offering better sealing performance and compensation capability.

Special Function Flat Washers
Conductive Flat Washer: Made of copper or copper alloy, used where electrical conductivity is required.
Corrosion/Anti-rust Flat Washer: Surface treated with galvanization, phosphating, etc., suitable for humid or corrosive environments.
Non-metallic Flat Washer: Made of materials such as rubber, asbestos, or PTFE, used for sealing, insulation, or vibration damping, but not considered traditional "metal flat washers."