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
| A335
  Seamless Steel Pipe Description | 
| ASTM
  A335 Pipe is a seamless ferritic alloy-steel
  Pipe for high temperature service. Pipe of this specification are suitable for bending, flanging, and similar forming
  operations, and for fusion welding. Generally, ASTM A335 P11, P22, and
  P91 pipelines are used for power generation and downstream oil and gas, and
  P5 and P9 grades are used for refinery applications. A335 steel pipe not only has high oxidation resistance and high
  temperature steam corrosion resistance,but also has good impact
  toughness,stable durable plasticity and thermal strength. A335 steel pipes are commonly
  used to transport high-temperature and high-pressure oil, natural gas and
  other media. | 
| Product   Parameters | 
| Product Name | A335 Seamless Steel Pipe | 
| Standard | EN/DIN/JIS/ASTM/BS/ASME/AISI etc. | 
| Outer Diameter | Seamless: 1/4"-36" | Welding: 21.3mm-3620mm | 
| Round Tube: 1/2"-10" | Square   Tube/Rectangular Tube: 15x15mm-400x600mm | 
| Wall   Thickness | Seamless: 1.25mm-50mm | Welding: 1.65mm-65mm | 
| Length | 3-12 meters, Support customization | 
| Surface Process | Bright, Polished, Black | 
| Other   Services | Machining(cnc), Centerless Grinding(cg), Heat   Treatment, Annealing, Pickling, Polishing, Rolling, Forging, Cutting,   Bending, Small Machining, etc. | 
| Chemical Composition | 
| A335 | UNS | C≤ | Mn | P≤ | S≤ | Si≤ | Cr | Mo | 
| P1 | K11522 | 0.10~0.20 | 0.30~0.80 | 0.025 | 0.025 | 0.10~0.50 | - | 0.44~0.65 | 
| P2 | K11547 | 0.10~0.20 | 0.30~0.61 | 0.025 | 0.025 | 0.10~0.30 | 0.50~0.81 | 0.44~0.65 | 
| P5 | K41545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 | 
| P5b | K51545 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.00~2.00 | 4.00~6.00 | 0.44~0.65 | 
| P5c | K41245 | 0.12 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 4.00~6.00 | 0.44~0.65 | 
| P9 | S50400 | 0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.50~1.00 | 8.00~10.00 | 0.44~0.65 | 
| P11 | K11597 | 0.05~0.15 | 0.30~0.61 | 0.025 | 0.025 | 0.50~1.00 | 1.00~1.50 | 0.44~0.65 | 
| P12 | K11562 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 0.80~1.25 | 0.44~0.65 | 
| P15 | K11578 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 1.15~1.65 | - | 0.44~0.65 | 
| P21 | K31545 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 2.65~3.35 | 0.80~1.60 | 
| P22 | K21590 | 0.05~0.15 | 0.30~0.60 | 0.025 | 0.025 | 0.5 | 1.90~2.60 | 0.87~1.13 | 
| P91 | K91560 | 0.08~0.12 | 0.30~0.60 | 0.02 | 0.01 | 0.20~0.50 | 8.00~9.50 | 0.85~1.05 | 
| P92 | K92460 | 0.07~0.13 | 0.30~0.60 | 0.02 | 0.01 | 0.5 | 8.50~9.50 | 0.30~0.60 | 
| Tensile   Strength Ksi | Elongation % | 
| 55 | 30 | 
| 55 | 30 | 
| 70 | 30 | 
| 60 | 30 | 
| 60 | 20 | 
| 60 | 30 | 
| 60 | 30 | 
| 85 | 20 |