Valve bonnet is an another important part of most valves. The bonnet is connected with valve body by a threaded, bolted, or welded joint connections. When dismantled from the body, the bonnet allows the access to the internal components of the valve for maintenance activities or replacement of parts. Bonnets are available in many designs and models such as bolted, round bolted, welded, pressure seal, etc. Valve bonnets are usually manufactured in cast steel or forged steel.