American Iron and Steel Institute: AISI

Steels Products Manual—Elat Rolled Electrical Steel, American Iron and Steel Institute (AISI), Washington, D.C., 1978. 

A typical low-alloy grade [American Iron and Steel Institute (AISI) 4340] contains 0.40 percent C, 0.70 percent Mn, 1.85 percent Ni, 0.80 percent Cr, and 0.25 percent Mo. Many other alloying agents are used to produce a large number of standard AISI and proprietary grades. 

When possible, earlier widely used three- or four-digit alloy numbering systems such as those developed by the Aluminum Association (AA), Copper Development Association (CDA), American Iron and Steel Institute (AISI), etc., have been incorporated by the addition of the appropriate alloy-group code letter plus additional digits. For example ... 

A four- or five-digit numbering system has been established to classify and identify different types of steel. Originally developed by the Society of Automotive Engineers (SAE) this system is now used by the American Iron and Steel Institute (AISI) to classify steel. 

Because of the many types of rolled and forged steel products used in industry, basic specifications are needed to designate the various types. The American Iron and Steel Institute (AISI) has set up a series of standards for steel products. However, even the relatively simple product descriptions provided by AISI and shown in Table 2 must be used carefully. For instance, the AISI 1020 carbon steel does not refer to all 0.20 percent carbon steels. AISI 1020 is part of the numerical designation system defining the chemical composition of certain standard steels used primarily in bar, wire, and some tubular steel products. The system almost never applies to sheets, strip, plates, or structural material. One reason is that the chemical composition ranges of standard steels are unnecessarily restrictive for many applications. 

Stainless steel classifications are based on material properties, method of fabrication and use of the end product. There are various societies, institutes, and so on, that classify stainless steel according to their own concerns and uses. You will most frequently run across the classifications from the American Iron And Steel Institute (AISI) and the American Society For Testing And Materials (ASTM). 

The use of iron-base metallic sutures started as early as 1666. The most commonly used metallic suture now is stainless steel, which is an alloy of mainly iron, chromium and nickel. However, due to the wide range of possible alloy compositions, the incorporation of trace elements, and fabrications, there are many different grades of stainless steels (Sutow, 1990). The three-digit classification of stainless steel is based upon the main composition in the alloy stipulated by the American Iron and Steel Institute (AISI) ... 

Carbon steels are basically alloys of iron and carbon, vtfith only small amounts of other elements present. For most of the steels discussed here, the carbon content ranges up to 1 %. However, there are some specialty steels in which carbon content may range up to 2 %. Carbon steels always contain some manganese, silicon, phosphorus, and sulfur minor amounts of other elements may also be present. The American Iron and Steel Institute (AISI) specifies that carbon steel may contain up to 1.65 % manganese, 0.6 % silicon, and 0.6 % copper [i]. 

Materials of construction can be related to the two most commonly used standards that are the American Iron and Steel Institute (AISI) and the German Werkstoff material numbers and their mean (average) chemical compositions. Note that chemical compositions will always differ from data in one book to another book and from one manufecturer s tool stock list to another. As an example it will be very unlikely that the P20 steel being used will exactly match the chemical composition reported in different tables. However they will be close. 

American Iron and Steel Institute (AISI) http //www.steel.org (accessed November 3, 2010). AISI represents Canadian, U.S., and Mexican steelmakers. Produces standards, including a compilation of out-of-date sections. 

American Iron and Steel Institute (AISI) http //www.steel.org (accessed August 12, 2010). AISI began in 1855 as the American Iron Association and serves as the voice of the North American steel industry in the public policy arena and advances the case for steel in the marketplace as the preferred material of choice. AISI also plays a lead role in the development and application of new steels and steehnaking technology. AISI is comprised of 24 member companies, including integrated and electric furnace steelmakers, and 138 associate and affiliate members who are suppliers to or customers of the steel industry. AISFs member companies represent approximately 75% of both U.S. and North American steel capacity (from Web page). 

The grade of stainless steel is also important. It is recognized that the lower grades, such as American Iron and Steel Institute AISI 304 and AISI 321, do not have sufficient corrosion protection, particularly if the material is work hardened. AISI 316 is the most popular choice since it has up to 18.5% chromixxm, a metal whose presence helps to build up a passive protective film of oxide and prevents corrosion. Together with 10 to 14% nickel content, the steel has an austenitic structure that is veiy ductile and easily welded. 

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