This reference work on metals and alloys aims to help the reader to identify the composition of materials and provides further data on mechanical properties where applicable. Trade names, symbols and specifications are listed and classified in groups according to chemical analysis. Each group of materials lists physical properties, such as electrical conductivity and melting points. The reader can therefore identify and make a comparison between similar materials from a knowledge of a specification or trade name, at the same time evaluating the physical and mechanical properties. This 4th edition has been revised and updated to include new material on the proliferation of welding rod and wire trade names, duplex stainless steels and the inclusion of the Unified Number Systems (UNS) codes. These codes have been issued as a result of an agreement between the Society of Automotive Engineers and the American Society for Testing Materials to cover trade names, codes and specifications used in the USA.