|The workers pouring a molten alloy steel into mold|
|Alloy steels comprise a wide variety of steels which have compositions that exceed the limitations of C, Mn, Ni, Mo, Cr, Va, Si, and B which have been set for carbon steels. However, steels containing more than 3.99% chromium are classified differently as stainless and tool steels.|
|Typically, alloy steels are designated by distinct AISI (American Iron and Steel Institute) four-digit numbers. The first two digits indicate the leading alloying elements, while the last two digits give the nominal carbon content of the alloy in hundredths of a percent. Occasionally we see five-digit designations where the last three digits tell that the carbon is actually over 1%. Here is an example: |
If a B shows up between the second and third digits of an AISI number, it means that this grade is a Boron steel; Sometimes a suffix H is attached to a AISI number to indicate that the steel has been produced to prescribed hardenability limits.