Low-carbon steel refers to steel containing less than 0.25% carbon, low strength, low hardness and softness. It includes most of ordinary carbon steel and high-quality carbon structural steel, most of which are not used for heat treatment in engineering structures, but also for some mechanical parts required for carburizing heat treatment and other wear. Low carbon steel annealed ferrite and pearlite strength and hardness, ductility and toughness are low. Therefore, cold forming performance is good, and cold forming methods such as crimping, bending and punching can be performed. This mild steel pipe weldability. Mild carbon steels with carbon contents ranging from 0.10 to 0.30% are easy to accept for a variety of processes such as forging, welding and cutting, commonly used in the manufacture of chains, rivets, bolts, shafts and more.
Common
mild steel pipe for building components, containers, tanks, furnaces and agricultural machinery. High-quality low-carbon steel pipe for the manufacture of car cabs, hoods and other crimson products; also rolled into bars, the strength required for the production of mechanical parts. Before the general use without heat treatment of steel pipe, the carbon content of more than 0.15%, carburizing or cyanidation for surface temperature requirements, good wear resistance bushings, bushings, sprockets and other parts. Due to the low strength of mild steel, the use is limited. Appropriate to increase the carbon content of manganese, adding trace amounts of vanadium, titanium, niobium and other alloying elements, can greatly enhance the strength of steel. If you lower the carbon content in the steel and add a small amount of aluminum, and a small amount of boron carbide to form elements, you can set the strength high enough for ultra-low carbon bainitic steels to remain good ductility and toughness.
Low-carbon steel with low carbon content, low hardness, poor processing, normalizing process can improve the cutting performance. Mild steel often has greater timeliness, both the tendency of quenching aging, but also the trend of strain aging. When rapid cooling of high temperature steel, ferrite scraping carbon, nitrogen saturation, it also slows the formation of iron carbonitride is at room temperature, and therefore its lower strength and hardness of steel, plasticity and toughness, a phenomenon known as quenching aging. Even without quenching, low carbon air cooling can cause aging. A large amount of low-carbon steel is produced by deformation dislocations. Ferrite is caused by the elastic dislocations of carbon and nitrogen atoms, and carbon atoms and nitrogen atoms gather on the wrong straight line. This combination of carbon and nitrogen atoms and dislocation lines is called the Coriolis year air mass (Krypton air mass). This will increase the strength and hardness of the steel while reducing ductility and toughness, a phenomenon known as strain aging. Low-carbon steel in the hardening process of aging hardening plasticity and toughness, the tensile curve on the risk of obvious upper and lower yield point. As the yield point elongation occurred until the end, there was a deformation of the folds formed on the surface due to the inhomogeneous surface and the sample, which was called the Rudds band. So many stampings are often scrapped. There are two ways to prevent it. High pre-deformation method, pre-deformed steel stamping area will produce a period of Ludes band, so pre-deformed steel stamping place not too long ago. Another type of steel, aluminum or titanium forms a stable compound with nitrogen to prevent the formation of air quality caused by Coriolis deformation.
