A low carbon steel pipe is a steel pipe having a low carbon content of less than 0.25% because of its low strength, low hardness, and softness. It includes most of the ordinary carbon steel and high quality carbon steel structural steel, most of which do not have the heat treatment used in the engineering structure, some carburizing heat treatment and other mechanical parts that require wear. The low carbon steel annealed microstructure of ferrite and pearlite has lower strength and hardness, and lower ductility and toughness. Therefore, the cold formability is good, and a cold forming method such as crimping, bending, or punching can be employed. A low carbon steel pipe like that has good weldability. Low carbon steel has a carbon content of 0.10% to 0.30%, and is easy to accept various processes such as forging, welding and cutting. It is commonly used in the manufacture of chains, rivets, bolts, shafts, etc.
Ordinary low carbon steel pipes are used to produce building components, containers, tanks, furnaces and agricultural machinery. High-quality low-carbon steel pipes are used to manufacture deep red products such as automobile cabs and engine covers; they can also be rolled into steel parts for production of mechanical parts with high strength requirements. Low-carbon steel pipes are generally not heat-treated before use, and their carbon content exceeds 0.15%. They are treated by carburizing or cyanide, and are used for parts requiring high surface temperature, worn shafts, bushings, sprockets, etc. Due to the low strength of low carbon steel, the use is limited. Appropriately increasing the carbon content of manganese and adding trace amounts of alloying elements such as vanadium, titanium and niobium can greatly increase the strength of steel. If the carbon content in the steel is lowered, a small amount of aluminum and a small amount of boron carbide forming element are added, and a ULCB having a sufficiently high strength can be obtained, and good ductility and toughness are maintained.
The low carbon steel pipe has low hardness and poor workability, and the normalizing process can improve the processability. Low-carbon steel pipes tend to have greater timeliness, both quenching and aging tendencies, and strain-aging tendencies. When rapidly cooled from high temperature steel, ferrite scrapes carbon and nitrogen saturation, which also slows the formation of iron carbonitride at room temperature, thereby reducing the strength and hardness of steel and reducing the ductility and toughness of steel. The phenomenon is called quenching aging. Aging can occur even without quenching and low carbon air cooling. Ferrite and carbon dislocations are deformed by deformation, nitrogen atoms interact with elastic dislocations, and carbon and nitrogen atoms are concentrated near the wrong line, producing a large amount of low carbon steel. This combination of carbon and nitrogen atoms and dislocation lines is known as the Coriolis age air mass (Ke-Lop air mass). It increases the strength and hardness of the steel while reducing ductility and toughness. This phenomenon is called strain aging. The quenching aging of lower carbon steel pipes in the process of deformation plasticity and toughness, the greater risk in the tensile curve has obvious upper and lower yield points. Since the yield extension at the yield point occurs to the end point, the deformation occurs because the surface is uneven and wrinkles are formed on the surface of the sample, called the Lutheran belt. Many stampings are often scrapped. There are two ways to prevent it. With the high pre-deformation method, the stamping of the pre-deformed steel plate will produce a stop band after a period of time, so the pre-deformed steel plate should not be placed too long before being punched. Another steel, aluminum or titanium is added to form a stabilizing compound with nitrogen to prevent air mass formation due to aging deformation of Coriolis.