Carbon Steel: Properties, Production, Examples and Applications
Carbon steel is an iron-carbon alloy, which contains up to 2.1 wt.% carbon. For carbon steels, there is no minimum specified content of other alloying elements, however, they often contain manganese. The maximum manganese, silicon and copper content should be less than 1.65 wt.%, 0.6 wt.% and 0.6 wt.%, respectively.
Types of carbon steel and their properties
Carbon steel can be classified into three categories according to its carbon content: low-carbon steel (or mild-carbon steel), medium-carbon steel and high-carbon steel [1]. Their carbon content, microstructure and properties compare as follows:
| Carbon content (wt.%) | Microstructure | Properties | Examples | 
| Low-carbon steel | < 0.25 | Ferrite, pearlite | Low hardness and cost. High ductility, toughness, machinability and weldability | 
| Medium-carbon steel | 0.25 – 0.60 | Martensite | Low hardenability, medium strength, ductility and toughness | 
| High-carbon steel | 0.60 – 1.25 | Pearlite | High hardness, strength, low ductility | 
Carbon Steel Description
Grade:
1)GB: Q195, Q215, Q235A, Q235B, Q235C, Q235D, Q255A, 255B, Q275, Q295A, Q295B, Q345B, Q345C, Q345D, Q345E, Q390A, Q390B, Q390C,Q390D, Q390E, Q420, Q420B, Q420C, Q420D, Q420E, Q460D, Q460E, Q500D, Q500E, Q550D, Q550E, Q620D, Q620E, Q690D, Q690E
2)EN: S185,S235JR, S275JR, S355JR, S420NL, S460NL S500Q, S550Q, S620Q, S690Q 
3)ASTM: Grade B, Grade C, Grade D, A36, Grade 36, Grade 40, Grade42, Grade 50, Grade 55, Grade 60, Grade 65, Grade 80 
4)JIS: SS330, SPHC, SS400, SPFC, SPHD, SPHE
PRODUCT DETAILS
| 1045
  Cold Rolled Steel Coil | 
| AISI
  1045 is a medium carbon steel designed to be able to function in areas
  requiring greater strength and hardness. This steel possesses excellent size
  accuracy, concentricity, and straightness which together minimize wear in
  high speed applications. AISI 1045 can be formed into turned, ground and
  polished coils that
  can be machined unsymmetrically with limited distortion. They are often used in the production
  of gears, shafts, axles, bolts, studs and
  machine parts. | 
| Product
  Parameters | 
| Product
  Name | 1045 Cold
  Rolled Steel Coil | 
| Production
  Process | Hot Rolling,
  Cold Rolling | 
| Material
  Standards | AISI, ASTM,
  ASME, DIN, BS, EN, ISO, JIS, GOST, SAE, etc. | 
| Width | 100mm-3000mm | 
| Length | 1m-12m, or
  Customized Size | 
| Thickness | 0.1mm-400mm | 
| Delivery
  Conditions | Rolling,
  Annealing, Quenching, Tempered or Standard | 
| Surface
  Process | Ordinary, Wire
  Drawing, Laminated Film | 
| Chemical
  Composition | 
  | 
| Element | Content (%) | 
| Carbon,
  C | 0.43-0.50 | 
| Manganese, Mn | 0.60-0.90 | 
| Sulfur, S | 0.05
  (max) | 
| Phosphorous, P | 0.04
  (max) | 
| Iron, Fe | Balance | 
| Mechanical
  Properties | 
| Properties | Metric | Imperial | 
| Tensile
  strength | 585 MPa | 84800 psi | 
| Yield strength | 450
  MPa | 65300
  psi | 
| Modulus of elasticity | 200
  GPa | 29000
  ksi | 
| Shear modulus (typical for steel) | 80
  GPa | 11600
  ksi | 
| Poisson’s ratio | 0.29 | 0.29 | 
| Elongation at break (in 50 mm) | 12% | 12% | 
| Hardness, Brinell | 163 | 163 | 
| Hardness, Knoop (converted from Brinell hardness) | 184 | 184 | 
| Hardness, Rockwell B (converted from Brinell hardness) | 84 | 84 | 
| Hardness, Vickers (converted from Brinell hardness) | 170 | 170 | 
| Scope of
  Application | 
| The
  following are the application areas of AISI 1045 carbon steel: | 
| ● Bolts | 
| ● Studs | 
| ● Gears | 
| ● Axles | 
| ● Shafts | 
| ●
  Machine parts. |