Material to manufacture rigging points for quality carbon structural steel and ordinary carbon steel, two, content of sulfur, phosphorus and other non-metallic inclusions of low. According to carbon content and different purposes, this kind of steel is roughly divided into three categories: less than 0.25%C for low carbon steel, especially the carbon containing less than 0.10% 08F, the 08Al, has a very good deep drawing and welding properties and is widely used for deep drawing parts such as automotive, manufacturing...... Etc.. 20G is the major material for manufacturing the ordinary boiler. In addition, the low carbon steel is widely used as a carburizing steel, used in the mechanical manufacturing industry. In the 0.25 ~ 0.60%C in carbon steel, used in quenched and tempered condition, make the mechanical manufacturing industry parts. It is more than 0.6%C for high carbon steel, used for the manufacture of springs, gears, rollers etc.. According to the manganese content is different, can be divided into ordinary manganese content (0.25 ~ 0.8%) and high manganese content (0.7 ~ 1% and 0.9 ~ 1.2%) of two steel group. Manganese can improve the permeability of hardened steel, strengthened ferritic steel, improve the yield strength, tensile strength and wear resistance. Usually in the high manganese steel grades after additional marked "Mn", such as 15Mn, 20Mn which is different from the normal amount of carbon steel containing manganese.