In
mechanical structures, we use different kinds of washers and bolts. A washer is thin plate generally disk-shaped with a hole in the middle. It is used to distribute load of threaded fastener like screw, nut or bolt. These are used for many other applications also. The industrial engineering is almost impossible without these. These are used to make the joints more reliable and long lasting. Alternatively these are commonly used as a spacer, spring, these have outer diameter about twice the size of inner diameter.
These small rings are usually made of metal, rubber or plastic. High quality joint needs hardened steel washer to prevent loss of pre-load because of Brinelling after the application of torque. Fiber or Rubber gaskets are used in taps, faucets or valves etc to stop the flow of water. In industrial applications these are used to seal the leakages of fluids through ports. Gaskets and washers look almost similar but both are designed for entirely different functions. Both are made with different materials also. Washer is used to prevent galvanic corrosion particularly by insulating the steel screws from aluminum surface.
Washers are made of using IS:2062 Grade A, En-8, En-19, SS-410, SS-304, SS-316 or any other material as per customer's requirement. These are blackodised, Phosphated and Zinc Plated with yellow, blue, olive green passivation to make them more sturdy as well as environmental friendly. Type B Punched Washers are used for round & cheese head screws. Type A Punched rings are used for hex bolts & screws.
These can be categorized into three types. Plain type spreads a
load and prevents the damage to the fixed surface. These provide some electrical insulation but this depends upon the material used to make that washer. Spring type washer has axial flexibility. It is used to prevent the loosening of joints because of vibrations. Locking type washers prevent loosening the joints and fastening by checking unscrewing rotation of fastened device.
The other small but commonly used industrial component is Anchor bolts. Cast-in-place is the simplest form of this bolt. These are extensively used on various types of construction related to buildings, dams and nuclear power plants etc.
