Structural steel constructional steel
Is in line with a specific level of strength and formability of steel. Formability by tensile elongation test, said after the interruption. Structural steel is generally used for carrying purposes, in the strength of steel in these applications is an important design criteria. Structural steel can be broken down as follows: Carbon steel, alloy structural steel heat-resistant low-alloy structural steel structural steel, and so on.
     Quality carbon structural steel and structural steel compared to ordinary carbon, sulfur, phosphorus, and other non-metallic inclusions at low levels. Based on carbon content and the use of different type of steel roughly divided into three categories:
     1 is less than 0.25% C low carbon steel, especially in the less than 0.10% carbon 08F, 08Al, etc., as has a good deep drawing and welding and is widely used as a deep-drawing parts such as automobile, can ... etc., 20G is the main production of common boiler materials, in addition, low-carbon steel is also widely used as case-hardened steel for machinery manufacturing,
     2. 0.25 ~ 0.60% C for the medium carbon steel, quenched and tempered condition than in the use, production of machinery parts manufacturing industry. Quenched much 22 ~ 34HRC, mechanical properties can be also easy to cut.
     3 greater than 0.6% C high carbon steel, used for manufacturing gear ﹑ ﹑ spring rolls, etc., according to the different amount of manganese, Mn can be divided into common (0.25 to 0.8%) and high Mn (0.7 ~ 1.0% and 0.9 ~ 1.2%), two steel groups. Manganese can improve the hardenability of steel, ferritic strengthen and improve the yield strength of steel ﹑ tensile strength and wear resistance. Usually in the high-manganese steel grades after the additional markings "Mn", such as 15Mn 20Mn ﹑ to distinguish them from the normal amount of carbon manganese steel.
     Carbon tool steel carbon content between 0.65 and 1.35%, obtained after heat treatment of high hardness and high wear resistance, mainly for the manufacture of cutting tools ﹑ ﹑ dies and gages.