The classification of the steel

Is the iron, carbon steel as the main composition of the alloy, its carbon content is less than 2. 11%. Steel is the very important in the economic construction of metal materials. According to the chemical composition are divided into carbon steel (steel Carbon steel) With alloy steel two kinds big. Carbon steel is an alloy of obtained by pig iron smelting, in addition to iron, carbon as its main ingredient, also contains a small amount of impurities such as manganese, silicon, sulfur and phosphorus. Carbon steel has certain mechanical properties, and have good process performance, and low cost. As a result, won the wide application of carbon steel. But with the rapid development of modern industry and science and technology, the performance of the carbon steel can not completely meet the need, so people all kinds of alloy steel was developed. Alloy steel is on the basis of carbon steel, purposefully to join some elements ( Known as alloying elements) And the multivariate alloy. With carbon steel, alloy steel performance has significantly improved, so the application is becoming more and more widely. Due to the steel variety, in order to facilitate production, storage, use and research, must be classified for steel. According to use classification according to the purpose of the steel can be divided into structural steel, tool steel, special steel three types of performance. Structural steel: 1. Used for steel of various kinds of machine parts. It includes carburizing steel, quenched and tempered steel, spring steel and bearing steel. Used as engineering structure steel. It includes a, b in carbon steel, special steel and ordinary low alloy steel. Tool steel, used to make all kinds of tool steel. According to the tool USES different can be divided into cutting tool steel and die steel and measuring tool steel. Special steel performance: is a special physical and chemical properties of the steel. Can be divided into stainless steel, heat-resistant steel, wear-resistant steel, magnetic steel, etc. According to the classification according to the chemical composition of steel chemical composition can be divided into two categories, carbon steel and alloy steel. Can be divided into the low carbon steel (carbon steel: according to the carbon content Carbon content 0 or less. 25%) ; Medium carbon steel ( 0. < 25% carbon content < 0. 6%) ; High carbon steel ( Carbon content or 0. 6%) 。 Alloy steel: can be divided into the low alloy steel (according to the content of alloying elements Alloy element content of total 5% or less) ; Alloy steel ( Alloy element content of total = 5% - 10%) ; High alloy steel ( Alloy element total content> 10%) 。 In addition, according to the different main alloy element content in the steel, also can be divided into manganese steel, chrome steel, chromium nickel steel, chromium manganese titanium steel, etc. According to the quality of classification according to the content of harmful impurity phosphorus and sulfur in steel can be divided into ordinary steel ( Phosphorus content 0 or less. 045%, sulfur content 0 or less. 055%; Or phosphorus, sulfur content is 0 or less. 050%) ; High quality steel ( Phosphorus, sulfur content is 0 or less. 040%) ; High quality steel ( Phosphorus content 0 or less. 035%, sulfur content 0 or less. 030%) 。 In addition, according to the types of furnaces, steel can be divided into open hearth steel ( Open hearth furnace, acid basic open-hearth) Converter steel, air, Bessemer converter, Thomas, oxygen top-blown converter steel) With the electric steel. Deoxidizing degree according to the smelting, steel can be divided into rimming steel ( DNA is not completely) , killed steel ( DNA is completely) And half killed steel. Steel mills in the steel product naming, tend to use, composition, quality of the three combined classification method. If the steel is called the ordinary carbon structural steel, high quality carbon structural steel, carbon tool steel, high quality carbon tool steel, alloy structural steel, alloy tool steel, etc.