322 Section 4 Nonferrous Metallurgy Goodheart-Willcox Publisher Figure 15-1. The UNS numbering system defines the composition of all commercial alloys, save those for medical and dental purposes. UNS Alloy Categories UNS series Metal type(s) A00001 to A99999 Aluminum and aluminum alloys C00001 to C99999 Copper and copper alloys D00001 to D99999 Specified mechanical property steels E00001 to E99999 Rare earth and rare earthlike metals and alloys F00001 to F99999 Cast irons G00001 to G99999 AISI and SAE carbon and alloy steels (except tool steels) H00001 to H99999 AISI and SAE H-steels J00001 to J99999 Cast steels (except tool steels) K00001 to K99999 Miscellaneous steels and ferrous alloys L00001 to L99999 Low-melting metals and alloys M00001 to M99999 Miscellaneous nonferrous metals and alloys N00001 to N99999 Nickel and nickel alloys P00001 to P99999 Precious metals and alloys R00001 to R99999 Reactive and refractory metals and alloys S00001 to S99999 Heat and corrosion-resistant (stainless) steels T00001 to T99999 Tool steels, wrought and cast W00001 to W99999 Welding filler metals Z00001 to Z99999 Zinc and zinc alloys Composition Processes Microstructure Properties Goodheart-Willcox Publisher Figure 15-2. The composition of a metal, the processes the metal goes through, and the microscopic structure produced in the metal all link together to produce the final properties of the metal. This logic flow is the same for nonferrous metals as for ferrous metals. 15.1 Atomic Structures in Metal Drive Unique Properties As you learned in Chapter 4, the four defining properties of metals are electrical conductivity, thermal conductivity, formability, and reflectivity. Atoms are made up of the subatomic particles electrons, protons, and neutrons, and the properties of metals are directly related to the way electrons behave within the metals. Recall also from Chapter 4 that large solid collections of metal atoms develop regions of precise order called crystals. 15.1.1 Unit Cells The unit cell is the smallest structure that repeats itself through the crystal. In solid metals, atoms form Copyright Goodheart-Willcox Co., Inc.