Alloy Designation Systems

Table 9.37 Major alloying elements in wrought alloys designation system ...

Notice however that for several common metal alloys (Mg, Al, Fe, etc.) special designation codes are used. As an example of the standard ASTM designation system, the codes used for the commercial magnesium alloys are shown in 5.12.4.5. 

Table 5.60. Magnesium alloys standard ASTM system of alloy (and temper) designation. An example of commercial alloy coding system.

Cayless, R.B.C. (1990) Alloy and temper designation systems for aluminum and aluminum alloys. In ASM Handbook, Vol.2, Properties and Selection Nonferrous Alloys and Special-Purpose Materials (ASM International, Materials Park, OH), p. 15. 

Temper Designation System. A temper designation is used for all forms of wrought and cast aluminum alloys. The temper designation... 

This family of stainless accounts for the widest usage of all the stainless steels. These materials are nonmagnetic, have face-centered cubic structures, and possess mechanical properties similar to the mild steels, but with better formability. The AISI designation system identified the most common of these alloys with numbers beginning with 300 and resulted in the term 300 series stainless. Table 3 lists the chemical analyses of some standard austenitic stainless steels and compares them to a few materials from other families of materials. 

The next section of this paper uses the Si3N4-Si02-AlN-Al203-YN-Y203 system to demonstrated the alloy design. 

Figure 2-5. AISI Designation System for carbon and low alloy steels consists of four numbers.

AA. Aluminum Association produced a four-digit system for wrought aluminum alloys and a three-digit system for cast alloys. Examples are alloys 6010 (wrought) and 356 (cast). A temper designation is also required. It follows the alloy designation and indicates the heat-treated or mechanically worked condition of the alloy such as 6010-T6. The T6 suffix indicates the alloy is in the precipitation hardened condition for optimum strength. 

UNS. Unified Numbering System satisfies the need for a common designation system for all alloys. The UNS number uniquely identifies the chemical composition of alloys that have been fixed by other organizations, such as one of the metal manufacturers associations. If the alloy is proprietary or produced by a limited number of suppliers, the chemical composition is established by the supplier. The... 

Figure 2-8. Unified Numbering System satisfies the need in the United States for a common designation system for all alloys.

Alloys are nsnally designated by the Unified Numbering System (UNS) [7, 8], which incorporates earlier identihcation systems developed for particular alloy families such as aluminum and copper alloys. The UNS system is particnlarly useful when designating proprietary alloys snch as the nickel-based alloys. Ordinary alloy designations that are nonproprietary, snch as those of the 300-series stainless steels, are commonly used instead of the UNS nnmber. 

Artificial disc replacemenfs have also been developed that do not incorporate UHMWPE components. These have a MOM bearing system, which presumably is to reduce the amoimt of wear produced. This once again shows the trend of borrowing concepfs from fhe TJR world and applying them to TDRs. In addition, for TDR designs, fhe wear performance of CoCr has been evaluated and was shown to have less wear rate in comparison with titanium alloy designs (Hellier, Hedman, and Kostuik 1992). 

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