The part that is placed between the connected part and the nut. It is generally a flat metal ring, which is used to protect the surface of the connected part from scratches by the nut and to disperse the pressure of the nut on the connected part.
split washer spring washer (general manufacturers will call washer 'Washi') flat washer flat washer
Flat washers are generally used in connectors, one of which is soft and the other is hard and brittle. Its main function is to increase the contact area, disperse the pressure, and prevent the soft texture from being crushed. The basic function of the spring of the spring washer is to give a force to the nut after the nut is tightened to increase the friction between the nut and the bolt! The material is 65Mn (spring steel), the heat treatment hardness is HRC44~51HRC, and the surface is oxidized.