tailieunhanh - MECHANICAL AND METALLURGICAL ANALYSIS OF STRUCTURAL STEEL

For a valve having a bonnet, the disk is the third primary principal pressure boundary. The disk provides the capability for permitting and prohibiting fluid flow. With the disk closed, full system pressure is applied across the disk if the outlet side is depressurized. For this reason, the disk is a pressure-retaining part. Disks are typically forged and, in some designs, hard-surfaced to provide good wear characteristics. A fine surface finish of the seating area of a disk is necessary for good sealing when the valve is closed. Most valves are named, in part, according to the design of their disks | NIST NCSTAR 1-3 Federal Building and Fire Safety Investigation of the World Trade Center Disaster Mechanical and Metallurgical Analysis of Structural Steel Frank W. Gayle Richard J. Fields William E. Luecke Stephen W. Banovic Timothy Foecke Christopher N. McCowan Thomas A. Siewert J. David McColskey NIST National Institute of Standards and Technology Technology Administration . Department of Commerce NIST NCSTAR 1-3 Federal Building and Fire Safety Investigation of the World Trade Center Disaster Mechanical and Metallurgical Analysis of Structural Steel Frank W. Gayle Richard J. Fields William E. Luecke Stephen W. Banovic Timothy Foecke Christopher N. McCowan Thomas A. Siewert J. David McColskey Materials Science and Engineering Laboratory National Institute of Standards and Technology September 2005 . Department of Commerce Carlos M. Gutierrez Secretary Technology Administration Michelle O Neill Acting Under Secretary for Technology National Institute of Standards and Technology William Jeffrey .