World Steel Numbering System
The World Steel Numbering System (WSN) is an international numbering system used to classify low alloy and alloy steels. The WSN system is managed by the World Steel Association (WSA) and provides a unified system for steel classification and numbering. The WSN system was first introduced in 1954 and was modified in 2016 to include additional grades and allow for better differentiation between low alloy and alloy steels.
The WSN system consists of two parts. The first part is the steel designation, which is used to identify the steel grade. The steel designation consists of a two-digit number that indicates the type of steel (low-alloy or alloy), followed by three digits that represent the specific alloying elements used in that steel grade. The second part of the system is the International Standard for the Classification of Steel (ISCS), which is used to classify steels according to their properties.
Steel grades are classified according to their chemical composition, tensile strength, hardenability, and mechanical properties. Low-alloy steels are classified by the first two digits of their steel designation, while alloy steels are classified by the first three digits. For example, a 4330 steel is a low-alloy steel that contains 0.3% nickel, 0.3% molybdenum, and 0.3% chromium; while a 4587 steel is an alloy steel that contains 0.8% nickel, 0.4% molybdenum, and 0.4% chromium.
The ISCS assigns a number to each steel grade according to its properties. This number is based on strength, toughness, hardenability, and other characteristics. The ISCS is used to compare the properties of different steel grades and helps to determine which steel grade is the most suitable for a particular application.
Low-alloy steels have a low carbon content, which makes them easier to weld and offers good wear resistance. They are often used in the automotive and construction industries. Alloy steels have higher carbon content and are used in applications that require higher strength and toughness. These steels are often used in petrochemical, aerospace, and defense industries.
In addition to the WSN system and the ISCS, there are several other steel number systems used around the world. These include the ASTM AISI (American Society for Testing and Materials) and the JIS (Japanese Industrial Standard). Each of these systems has its own unique numbering system for steel grades.
The WSN system and the other steel number systems provide a comprehensive set of tools for steel classification and numbering. The WSN system is used to classify and number low alloy and alloy steels, while the other systems are used for different types of steel. The WSN system provides a useful means of comparing different steel grades and selecting the best steel for a particular application.
