Supply high quality low carbon ST12 cold rolled steel plate

Low carbon steel, also known as mild steel, has a carbon content from . to .3. Low carbon steel is easy to accept various processing such as forging, welding and cutting. It is often used to make chains, rivets, bolts, shafts, etc. Carbon steel with a carbon content lower than . is also called mild steel because of its low strength, low hardness and softness. It includes most ordinary carbon structural steel and some high-quality carbon structural steel. Most of them are used for engineering structural parts without heat treatment, and some are used for mechanical parts requiring wear resistance after carburizing and other heat treatments. Characteristics
The annealed structure of low carbon steel is ferrite and a small amount of pearlite. Its strength and hardness are low, and its plasticity and toughness are good. Therefore, it has good cold formability and can be cold formed by curling, bending, stamping and other methods. This steel has good weldability. Low carbon steel with very low carbon content has very low hardness and poor machinability. Normalizing treatment can improve its machinability.
Low carbon steel has a greater aging tendency, including both quenching aging tendency and deformation aging tendency. When steel cools rapidly from high temperature, the ferrite scrapes carbon and becomes supersaturated with nitrogen. It can also slowly form iron carbonitrides at room temperature. Therefore, the strength and hardness of the steel increase, but the plasticity and toughness decrease. This phenomenon It is called quenching aging. Mild steel will age even if it is air cooled without quenching. Low carbon steel generates a large number of dislocations through deformation. Carbon and nitrogen atoms in the ferrite elastically interact with the dislocations, and the carbon and nitrogen atoms gather around the dislocation lines. This combination of carbon, nitrogen atoms and dislocation lines is called a Korotkis air mass.
It will increase the strength and hardness of steel but reduce its plasticity and toughness. This phenomenon is called deformation aging. Deformation is more harmful to the plasticity and toughness of low carbon steel than quenching aging. There are two obvious upper and lower yield points on the tensile curve of low carbon steel. From the appearance of the upper yield point to the end of the yield extension, a surface wrinkle zone formed due to uneven deformation appears on the surface of the specimen, which is called the Lüders zone. Many stamped parts are often scrapped because of this. There are two ways to prevent it. A high pre-deformation method. The pre-deformed steel will also produce Lüders bands when stamped after being placed for a period of time. Therefore, the pre-deformed steel should not be placed for too long before stamping. The other is to add aluminum or titanium to the steel to form a stable compound with nitrogen to prevent deformation and aging caused by the formation of Coriolis gas clusters.
Type
Low carbon steel is generally rolled into angle steel, channel steel, I-beam, steel pipe, steel strip or steel plate, and is used to make various building components, containers, boxes, furnaces and agricultural machinery, etc. . High-quality low-carbon steel is rolled into thin plates to make deep-drawn products such as car cabs and engine hoods. It is also rolled into bars for making mechanical parts with low strength requirements. Low carbon steel generally does not undergo heat treatment before use. Those with carbon content above . Mild steel has limited use due to its lower strength. Appropriately increasing the manganese content in carbon steel and adding trace amounts of vanadium, titanium, niobium and other alloying elements can greatly improve the strength of the steel. If the carbon content in steel is reduced and a small amount of aluminum, a small amount of boron and carbide forming elements are added, an ultra-low carbon bainite group can be obtained which has high strength and maintains good plasticity and toughness.
Emerging uses
Originally, due to the inherent characteristics of low carbon steel, its range of use was greatly limited. With the application of some new domestic technologies in the steel industry, many emerging uses of low carbon steel have been well developed. At present, some large domestic steel mills or steel trading companies are actively cooperating closely with large domestic sling companies to jointly develop a series of high-tech, high-precision and high-quality rigging products. The industry has played a very good role in promoting technology. An example of this is the in-depth cooperation between Pree Steel and Hebei Changjiang COSCO Sling Co., Ltd. Many of the series of products they have developed have achieved high recognition in the industry. evaluation of. This also points out a new way for us to comprehensively utilize low carbon steel.
Mechanical Properties of Mild Steel
Mild steel is a plastic material. At the beginning, it follows Hooke's law and rises in a straight line. After the proportional limit, the deformation accelerates, but there is no obvious yield stage. Instead, the shape gradually curves upward. This is because after the proportional limit is exceeded, with the rapid growth of plastic deformation, the cross-sectional area of the specimen gradually increases, so the load it bears also increases.