Carbon steel remains one of the most widely used materials in industrial manufacturing, valued for its exceptional strength-to-cost ratio and versatile mechanical properties. For Southeast Asian manufacturers looking to sell on Alibaba.com, understanding the technical specifications of carbon steel is essential for communicating effectively with global B2B buyers.
Carbon steel is classified primarily by its carbon content, which directly influences hardness, tensile strength, and machinability. The three main categories are:
- Low Carbon Steel (Mild Steel): Contains 0.05-0.25% carbon. This is the most common grade for industrial components, offering excellent formability and weldability. Low carbon steel accounts for approximately 51.93% of the global carbon steel market share [1].
- Medium Carbon Steel: Contains 0.25-0.55% carbon. Provides higher strength and hardness than low carbon steel, making it suitable for machinery parts, automotive components, and high-stress applications.
- High Carbon Steel: Contains 0.55-1.0% carbon. Offers maximum hardness and wear resistance but reduced ductility. Commonly used for cutting tools, springs, and high-wear components.
For industrial components such as flanges, valves, pipe fittings, and fasteners, low to medium carbon steel grades (AISI 1018, 1020, 1045) are most commonly specified due to their balance of strength, machinability, and cost-effectiveness.
Carbon Steel Mechanical Properties by Grade (Typical Values)
| Grade | Carbon Content | Tensile Strength | Yield Strength | Elongation | Hardness (Brinell) | Common Applications |
|---|---|---|---|---|---|---|
| AISI 1018 (Low) | 0.15-0.20% | 400-440 MPa | 300-370 MPa | 15-20% | 120-140 HB | General machinery, shafts, pins |
| AISI 1020 (Low) | 0.18-0.23% | 410-450 MPa | 310-380 MPa | 15-20% | 130-150 HB | Bolts, nuts, light-duty parts |
| AISI 1045 (Medium) | 0.43-0.50% | 570-700 MPa | 450-550 MPa | 10-15% | 170-210 HB | Gears, axles, high-stress components |
| AISI 12L14 (Free-machining) | 0.15% max | 540 MPa | 415 MPa | 10% | 163 HB | High-volume machined parts |
| AISI 1095 (High) | 0.90-1.03% | 850-1100 MPa | 620-800 MPa | 5-10% | 250-300 HB | Cutting tools, springs, blades |
When listing carbon steel products on Alibaba.com, buyers expect detailed material certifications. Common standards include ASTM A105 (forged carbon steel fittings), ASTM A216 (cast carbon steel valves), and AISI/SAE grade designations. Providing mill test certificates (MTC) or material test reports (MTR) significantly increases buyer confidence and reduces inquiry-to-order conversion time.
It's important to note that carbon steel's mechanical properties can be enhanced through heat treatment processes such as annealing, normalizing, quenching, and tempering. These processes allow manufacturers to tailor material properties to specific application requirements without changing the base material grade.

