What kind of low carbon steel or medium carbon steel are they?
Low carbon steel (low carbon steel) as the carbon content of less than 0.25% of the carbon steel, because of its low strength, low hardness and soft, it is also called the mild steel. It includes most of the ordinary carbon structural steel and some high-quality carbon structural steel, most of which are not used for engineering structural parts without heat treatment. Some of them are used for wear-resistant mechanical parts after carburizing and other heat treatment.
Low carbon steel is generally rolled into angle steel, channel steel, I-beam, steel pipe, steel belt or steel plate. It is used to make all kinds of building components, containers, boxes, furnaces and agricultural machinery and so on. High quality low carbon steel is rolled into thin board, making deep drawing products such as automobile cab, engine cover, etc., also rolled into bars, used for making mechanical parts of low strength requirement. Low carbon steel is not treated by heat before use. The carbon content is above 0.15%. It is treated by carburizing or cyaniding. It is used for shaft, shaft sleeve, chain wheel and other parts which require high surface temperature and good wear resistance.
The annealed structure of low carbon steel is ferrite and a small amount of pearlite, its strength and hardness are lower, and its plasticity and toughness are better. Therefore, its cold forming property is good, and cold forming can be carried out by curling, bending and stamping. This kind of steel also has good weldability. Carbon content from 0.10% to 0.30% low carbon steel is easy to accept all kinds of processing, such as forging, welding and cutting. It is used to make chains, rivets, bolts, shafts and so on.
Low carbon steel is limited in use due to its low strength. Increasing the content of manganese in the carbon steel and adding some alloying elements such as vanadium, titanium and niobium can greatly improve the strength of the steel. If the carbon content in the steel is reduced and a small amount of aluminum, a small amount of boron and carbide are added to form the element, the super low carbon bainite can be obtained, and its strength is very high and good plasticity and toughness can be maintained
