Black Q235 Low Carbon Steel Coil Hot Rolled 0.17mm-3.5mm Wall Thickness

Hot Rolled 0.17 Mm-3.5 Mm Wall Thickness Black Q235 Low Carbon Steel Coil

Mild steel (Low carbon steel) is a carbon steel with carbon content less than 0.25%. It is also called mild steel because of its low strength, low hardness and softness. It includes most of the ordinary carbon structural steel and part of the high quality carbon structural steel, most of the engineering structural parts without heat treatment, and some of the carburizing and other heat treatment for wear-resistant mechanical parts.

The annealed structure of low carbon steel is ferrite and a little pearlite, with low strength and hardness, good plasticity and toughness. Therefore, its cold formability is good, can be used to roll, bending, stamping and other methods for cold forming. This steel also has good weldability. Low carbon steel with carbon content from 0.10% to 0.30% is easy to accept all kinds of machining such as forging, welding and cutting, and is often used in the manufacture of chains, rivets, bolts, shafts, etc.

The annealed structure of low carbon steel is ferrite and a little pearlite, with low strength and hardness, good plasticity and toughness. Therefore, its cold formability is good and can be used for cold forming methods such as crimping, bending and stamping. This kind of steel has good weldability. Low carbon steel with very low carbon content has very low hardness and poor machinability, and normalizing treatment can improve its machinability.

Low carbon steel has a great aging tendency, both quenching aging tendency and deformation aging tendency. When the steel is cooled from high temperature, the carbon and nitrogen in the ferrite are in a supersaturated state, and it can slowly form the carbon and nitrogen of iron at room temperature, so the strength and hardness of steel are improved, and the plasticity and toughness are reduced, this phenomenon is called quenching aging. Low carbon steel will produce aging even if it is not hardened and air cooled. The carbon and nitrogen atoms in ferrite interact elastically with the dislocation, and the carbon and nitrogen atoms gather around the dislocation line. This combination of carbon and nitrogen atoms and dislocation lines is called a Corleone air mass. It will increase the strength and hardness of steel and decrease the plasticity and toughness, this phenomenon is called deformation aging. Deformation aging is more harmful to the ductility and toughness of low carbon steel than quenching aging, and there are 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 yield extension, a surface corrugation band, called Luders zone, is formed on the surface of the sample due to uneven deformation. Many stamping parts are often scrapped as a result. There are two ways to prevent it. A high pre-deformation method, pre-deformation of steel placed for a period of time after stamping will also produce luders zone, so the pre-deformation of steel before stamping place time should not be too long. The other is to add aluminum or titanium to the steel to form a stable compound with nitrogen that prevents the formation of deformation aging caused by the Collarian gas mass.