Carbon structural steel carbon structural steel of carbon steel. Carbon content about 0.05% ~ 0.70%, and individual can be as high as 0.90%. Can be divided into ordinary carbon structural steel and high quality carbon structural steel two kinds. The former with impurity is more, the price is low, used for performance requirements is not high place, the carbon content of its most under 0.30%, with manganese quantity does not exceed 0.80%, intensity is low, but plastic, toughness, cold deformation performance is good. Except a few circumstances, generally not heat treatment, use directly. Much is made of steel, steel plates, steel, etc. Is of much use, the dosage is very big, mainly used for railway, Bridges, and various types of construction engineering, manufacturing under the static load of all kinds of metal components and not important don't need heat treatment of mechanical parts and general welding parts. High quality carbon structural steel pure, little impurity, mechanical performance is good, by heat treatment after use. According to contain manganese content into ordinary with manganese quantity (less than 0.80%) and a higher amount with manganese (0.80% ~ 1.20%) two groups. Carbon content below 0.25%, more than the heat treatment used directly, or the cementite, carbon and nitrogen were permeability processing, manufacturing medium and small gear axle and piston pins; Carbon content in 0.25% ~ 0.60%, the typical GangHao 40,45,40 Mn, 45 Mn, etc, the coating processing, manufacturing all kinds of machine parts, fasteners, etc.; More than 0.60% of the carbon content, such as 65,70,85,65 Mn, 70 Mn, much as spring steel use. This kind of steel main ensure mechanical properties, so its brand reflects its mechanical properties,