Japanese JIS Steel Designation System Overview
The Japanese Industrial Standard (JIS) steel designation system is a Japanese standard for identifying a wide range of steel grades. It is the most commonly used steel designation system in the world. Steel grades can range from those produced in Japan to those produced in other countries, such as the United States, Canada, Germany, and the United Kingdom. The system was developed during the 1950s and 1960s, but has consistently evolved since then to reflect modern manufacturing needs and trends.
JIS steel grades are composed of three-part symbols, wherein each part has a specific meaning. The first part of the symbol refers to the ultimate material strength of the steel, while the second and third refer to the type of steel. The first part of the symbol consists of a letter which stands for the first letter of the material grade, such as S for high-carbon steels, SUS for stainless steels and C for cold rolled and cold worked steels. The second part of the system is a number which gives the nominal composition of the alloy in hundredths of percentages for the same material grade.
The third part of the symbol is an arbitrary number or two arbitrary numbers, separated by a hyphen. This part of the number gives an indication of the specific metallurgical characteristics of the steel. The second part of the symbol may have one of three forms: a single number, two separate numbers separated by a hyphen, or several numbers with no hyphen. All of these signify different grades within the material grade, as each of them refer to a different level of strength or alloying elements present in the steel.
The Japanese Steel Association (JSA) sets the standard for JIS steel designation system. When a JIS steel is manufactured by a Japanese manufacturer, the validity of the JIS steel designation is ensured by the Japanese industrial specification number printed on the manufactured material. This printed number is also checked by the Japanese authorities to certify the JIS steel designation from the manufacturer was correctly stated.
The JIS steel designation system is widely used throughout the world, as it is the system most used for referring to specific steel grades. It is particularly useful for steel parts used for automobiles, aircraft, and other machinery. This system ensures that the right type of steel, with the right amount of strength, is used for all applications. The fact that it is widely accepted, and the detailed information that is contains, makes the JIS steel designation system the most favored system of steel designation worldwide.
