Round steel is divided into three types: hot rolled, forged and cold drawn. The size of hot rolled round steel is 5.5-250 mm. Among them: 5.5-25 mm small round steel is mostly supplied in straight bundles, commonly used as reinforcement, bolts and various mechanical parts; Round steel larger than 25 mm, mainly used for manufacturing machine parts, seamless steel tube billets, etc.
Carbon steel can be divided into low carbon steel, medium carbon steel and high carbon steel according to its chemical composition (i.e. carbon content).
(1) low carbon steel
Also known as mild steel, carbon content from 0.10% to 0.30% low carbon steel is easy to accept a variety of processing such as forging, welding and cutting, often used in the manufacture of chains, rivets, bolts, shafts, etc.
(2) the medium carbon steel
Carbon steel with carbon content of 0.25% ~ 0.60%. Sedation steel, semi - sedation steel, boiling steel and other products. In addition to carbon, it can also contain a small amount of manganese (0.70% ~ 1.20%). According to the product quality is divided into ordinary carbon structural steel and high quality carbon structural steel. The hot working and cutting performance is good, but the welding performance is poor. The strength and hardness are higher than low carbon steel, and the plasticity and toughness are lower than low carbon steel. Without heat treatment, hot rolled or cold drawn materials can be used directly or after heat treatment. Medium carbon steel after quenching and tempering has good comprehensive mechanical properties. The highest hardness can be achieved is about HRC55(HB538), σb is 600 ~ 1100MPa. So in the various uses of medium strength level, medium carbon steel is the most widely used, in addition to as a building material, but also a large number of mechanical parts for manufacturing.
(3) high carbon steel
Often called tool steel, carbon content from 0.60% to 1.70%, can be hardened and tempered. Hammers, crowbars, etc. are made of steel with a carbon content of 0.75%; Cutting tools such as drills, taps and reamers are made of steel with a carbon content of 0.90% to 1.00%.
common steel grade:Q195、Q235、10#、20#、35#、45#、Q215、Q345、12Cr1Mov、15CrMo、304、316、20Cr、40Cr、20CrMo、35CrMo、42CrMo、40CrNiMo、GCr15、65Mn、50Mn、50Cr、3Cr2W8V、20CrMnTi、5CrMnMo