According to the quality of steel, it can be divided into ordinary carbon steel and high quality carbon steel.
(1) Common carbon structural steels, also known as ordinary carbon steels, have wide limits on carbon content, performance range and content of phosphorus, sulfur and other residual elements.In China and some countries according to the guarantee of delivery conditions and divided into three categories:
Class A steel (A steel) is to guarantee the mechanical properties of the steel.Class B steels (Class B steels) are steels with guaranteed chemical composition.Special steels (Class C steels) are steels that guarantee both mechanical properties and chemical composition, and are often used in the manufacture of more important structural parts.China produces and uses A3 steel (Class A No.3 steel) with a carbon content of about 0.20%, which is mainly used in engineering structures.
Some carbon structural steels also add small amounts of aluminum or niobium (or other carbide-forming elements) to form nitric or carbide particles to limit grain growth, strengthen the steel and save steel.In China and some countries, in order to meet the special requirements of professional steel, the chemical composition and properties of common carbon structural steels have been adjusted, thus a series of professional steel of common carbon structural steels (such as bridge, building, steel bar, pressure vessel steel, etc.) have been developed.
(2) Compared with common carbon structural steels, the contents of sulfur, phosphorus and other non-metallic inclusions in high quality carbon structural steels are lower.These steels are roughly classified into three categories, depending on their carbon content and use:
(1) less than 0.25%C is low carbon steel, especially the carbon containing less than 0.10% of 08F,08Al, etc., because of its good deep drawing and weldability and is widely used as deep drawing parts such as cars, cans......And so on.20G is the main material in the manufacture of ordinary boilers.In addition, low carbon steel is also widely used as carburizing steel for machinery manufacturing.
②0.25 ~ 0.60%C is medium carbon steel, which is mostly used under the condition of tempering and tempering, and is used to make parts for machinery manufacturing industry.
(3) > 0.6%C for high carbon steel, mostly used in the manufacture of springs, gears, rolls, etc.
According to the different manganese content, it can be divided into two steel groups with ordinary manganese content (0.25 ~ 0.8%) and high manganese content (0.7 ~ 1.0% and 0.9 ~ 1.2%).Manganese can improve the hardenability of steel, strengthen ferrite, and improve the yield strength, tensile strength and wear resistance of steel.Usually after the grade of the steel with high manganese content, the additional mark "Mn" is added, such as 15Mn, 20Mn to distinguish it from the normal carbon steel with manganese content.
2000-12000mm，or as required
Cold/Hot rolled, Cold-Drawn， or Hot Forged
Annealed; Quenched; Tempered
ISO, SGS，BV，Mill Certificate
FOB,CRF,CIF,EXW all acceptable
Carbon steels can be divided into low carbon steel, medium carbon steel and high carbon steel according to their chemical composition (that is, carbon content).
(1) low carbon steel
Also known as mild steel, with carbon content from 0.10% to 0.30%, mild steel is easy to accept a variety of machining such as forging, welding and cutting, and is often used in the manufacture of chains, rivets, bolts, shafts, etc.
(2) the medium carbon steel
Carbon content of 0.25% ~ 0.60% carbon steel.There are killed steel, semi - killed steel, rimmed steel and other products.In addition to carbon, it can also contain a small amount of manganese (0.70% ~ 1.20%).According to product quality, it can be divided into ordinary carbon structural steel and high quality carbon structural steel.Hot working and cutting performance is good, welding performance is poor.The strength and hardness are higher than that of low carbon steel, but the plasticity and toughness are lower than that of low carbon steel.Hot rolled and cold drawn materials can be used directly or after heat treatment without heat treatment.The medium carbon steel after quenching and tempering has good comprehensive mechanical properties.The highest hardness that can be achieved is about HRC55(HB538), σ B is 600 ~ 1100MPa.So in the various uses of the medium strength level, the medium carbon steel is the most widely used, in addition to as a building material, but also a large number of used in the manufacture of various mechanical parts.
(3) high carbon steel
Often referred to as tool steel, it contains carbon from 0.60% to 1.70% and can be hardened and tempered.Hammers, crowbars, etc. are made of 0.75% carbon steel;Cutting tools such as drill, wire tap and reamer are manufactured from steel with carbon content from 0.90% to 1.00%.
standard export packing (inside:water proof paper,outside:steel covered with strips and pallets)