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 . 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
| A572
  Round Steel Bar Description | 
| A572 steel bar is made of a low-carbon, low-alloy
  high-strength steel employing the electric furnace steelmaking technology. So the main component is scrap
  iron. Resulting from its reasonable composition design and strict process control,
  A572 steel bar is widely favored for high
  purity and excellent performance. Its molten
  steel pouring manufacturing method not only gives the steel coil good density and
  uniformity, but also ensures that the steel bar has superior mechanical properties after cooling. A572 carbon steel bar is
  widely used in construction, bridges, heavy machinery and other fields. At
  the same time, it shows outstanding performance in welding, forming and
  corrosion resistance with its low carbon and low alloy characteristics. | 
| Product
  Parameters | 
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| Product
  Name | A572/S355JR Round Steel Bar | 
| Standard | EN/DIN/JIS/ASTM/BS/ASME/AISI, etc. | 
| Common
  Round Bar Specifications | 3.0-50.8 mm, Over 50.8-300mm | 
| Flat
  Steel Common Specifications | 6.35x12.7mm, 6.35x25.4mm, 12.7x25.4mm | 
| Hexagon
  Bar Common Specifications | AF5.8mm-17mm | 
| Square
  Bar Common Specifications | AF2mm-14mm, AF6.35mm, 9.5mm, 12.7mm, 15.98mm, 19.0mm, 25.4mm | 
| Length | 1-6meters, Size Accept Custom | 
| Diameter(mm) | Hot Rolling
  Round Bar | 25-600 | Cold
  Rolling Square Bar | 6-50.8 | 
| Hot Rolling Square Bar | 21-54 | Cold
  Rolling Hexagon Bar | 9.5-65 | 
| Cold Rolling Round bar | 6-101.6 | Forged Rebar | 200-1000 | 
| Surface Process | Bright, Polished, Black | 
| Other
  Services | Machining(cnc), Centerless Grinding(cg), Heat
  Treatment, Annealing, Pickling, Polishing, Rolling, Forging, Cutting,
  Bending, Small Machining, etc. | 
| A572 | C | Mn | P | S | Si | 
| Grade42 | 0.21 | 1.35 | 0.03 | 0.03 | 0.15~0.4 | 
| Grade50 | 0.23 | 1.35 | 0.03 | 0.03 | 0.15~0.4 | 
| Grade60 | 0.26 | 1.35 | 0.03 | 0.03 | 0.4 | 
| Grade65 | 0.23~0.26 | 1.35~1.65 | 0.03 | 0.03 | 0.4 | 
| A572 | Yield Strength(Ksi) | Tensile
  Strength(Ksi) | Elongation % 8inches | 
| Grade42 | 42 | 60 | 20 | 
| Grade50 | 50 | 65 | 18 | 
| Grade60 | 60 | 75 | 16 | 
| Grade65 | 65 | 80 | 15 | 
| Physical
  Performance | Metric | Imperial | 
| Density | 7.80g/cc | 0.282 lb/in³ |