American Standard Steel Numbering System
The American Standard Steel Numbering System (ASNS) is an industry-wide system of standard numbers used to identify different steels. This system makes it easier for manufacturers, consumers, and suppliers to buy, use, and sell standard steel components quickly and accurately.
The ASNS system consists of four digits, each corresponding to a characteristic of the steel such as proportion and grain refinement. The first two digits represent the base metal or alloy. The third and fourth digits represent the extra elements or grain refining. These elements are divided into two broad categories: components that affect mechanical properties and components that affect physical properties.
At the beginning of this century, competitors from different industries were struggling to gain a foothold in the steel industry. To facilitate the buyers, suppliers, and manufacturers, a national standard for steel numbers was created by the American Iron and Steel Institute (AISI). This number series, called the AISI-SAE (Society of Automotive Engineers) Steel Numbering System, became the official identification system for steel components in North America.
The AISI-SAE steel numbers are arranged in increments to indicate different nuances of the steel; for instance, the last two digits can indicate the alloy composition, the heat-treat cycle, surface treatment, or other element combination. The most common numbering system used in the U.S. and Canada today is the ANSI/AISI or SAE designations. This system combines a three-digit numerical number to designate the type of steel and a fourth letter or number combination to denote the particular chemistry or heat treat cycle of the particular steel.
The numerical number represents the percentage of the five major alloying elements present: carbon, manganese, chromium, nickel, and silicon. For example, 1018 indicates a low carbon steel with an average combined content of 0.18% of copper, manganese and chrome. Similarly, 4340 indicates a low alloy steel containing 0.4% of carbon, with additional alloying elements of manganese, chromium, and nickel. Each additional letter and number combination may also represent additional alloying elements such as lead and molybdenum or grain refinement such as air hardening or strain-hardening.
The American Standard Steel Numbering System is a well-established and standardized system which has been around for over a century. It is used to identify and distinguish different types of steels in North America. As the steel industry advances and more components are introduced, the ASNS will continue to serve as a universal language for the steel industry, helping manufacturers and consumers stay up-to-date with the latest developments and trends.
