A washer is a resilient pad or card lock washer A washer that prevents bolts from loosening. The working principle of lock washers is very simple. It consists of two washers. The outside is a radial relief surface, and the inside is a helical tooth surface. When assembling, the inner helical tooth surfaces are opposed to each other, and the outer radial raised surface is in an engaged state with the contact surfaces at both ends. When the connecting piece is vibrated and the bolt tends to loosen, only the inner helical tooth surfaces of the two washers are allowed to face each other. Staggered movement produces lifting tension to achieve 100% locking. Gasket related information description 1. Grade C gaskets do not have Ra3.2 and deburring requirements. 2. Grade C is suitable for medium assembly series, Grade A is suitable for fine assembly series. Flat washer 3. G B848-85 is mainly used for screws with cylinder head, others are used for standard hexagon bolts, screws and nuts. 4. Material mechanical property grade: steel 200HV; austenitic stainless steel A200. 5. Marking example: standard series, nominal size du003d8mm, flat washer with performance grade of 200HV and no surface treatment: washer GB97.1—85 8 200HV.