Steel is one of the most commonly used and necessary metals for humanity. Many products in your home contain steel. Carbon steel stands out from other forms of steel due to its unique qualities, which make it highly valuable in a variety of industries.
Carbon steel’s strength, durability, and versatility make it excellent for a wide range of uses, including construction, manufacturing, automotive, and home items. Understanding the many varieties of carbon steel and their respective applications can help you grasp its significance in everyday life and diverse industries.
Definition of Carbon Steel
Carbon steel is a steel alloy that includes 0.12% to 2% carbon. Any steel can be categorized as carbon steel if it fails to meet the certified minimum standards for other key alloying elements.
For example, chromium, molybdenum, cobalt, nickel, tungsten, titanium, and zirconium are not used in carbon steel if they surpass specific limitations. This category also includes steel that has less than 0.4% copper.
Furthermore, carbon steel can refer to any steel containing more than 1.65% manganese or 0.6% copper. Essentially, any steel that is not categorized as stainless steel, including various alloy steels, is considered carbon steel.
Types and Properties of Carbon Steel
Carbon steel is divided into three categories based on carbon content: low-carbon steel (also known as mild steel), medium-carbon steel, and high-carbon steel. Here’s a comparison of their carbon content, microstructure, and properties:
| Type | Carbon content (%) | Microstructure | Properties | Examples |
| Low-carbon steel | 0.05 – 0.25 | Ferrite, pearlite | Low hardness and cost. High ductility, toughness, machinability and weldability | AISI 304, ASTM A815, AISI 316L |
| Medium-carbon steel | 0.30 – 0.50 | Martensite | Low hardenability, medium strength, ductility and toughness | AISI 409, ASTM A29, SCM435 |
| High-carbon steel | 0.60 – 1.00 | Pearlite | High hardness, strength, low ductility | AISI 440C, EN 10088-3 |
Characteristics and Properties of Medium Carbon Steel
Medium-carbon steel is distinguished by numerous essential characteristics that make it useful in manufacturing. It is noted for its strength and ductility, making it ideal for a variety of applications. This grade of steel responds well to heat treatment and can withstand harsh environments and the wear that comes with them. Our machinists choose medium-carbon steel because it is easier to work with than some other steel kinds. The following tables describe the physical and thermal properties of medium-carbon steel.
| Property | Value |
| PropertyYield Strength | Value420 Mpa |
| PropertyHardness | Value200 MPa |
| PropertyDensity | Value7.75–7.89 g/cm³ |
| PropertyMagnetism | ValueIt is typically magnetic |
Carbon Steel Chemical Compositions
| COMPONENT | WT. % |
| C | Max 0.15 |
| Fe | 97.91 – 98.7 |
| Mn | 0.85 – 1.15 |
| P | 0.04 – 0.09 |
| Pb | 0.15 – 0.35 |
| S | 0.26 – 0.35 |
Carbon Steel Physical Properties
| PHYSICAL PROPERTIES | METRIC | ENGLISH | COMMENTS |
| Density | 7.87 g/cc | 0.284 lb/in³ | Typical for steel |
Carbon Steel Mechanical Properties
| MECHANICAL PROPERTIES | METRIC | ENGLISH | COMMENTS |
| Hardness, Brinell | 163 | 163 | |
| Hardness, Knoop | 184 | 184 | Converted from Brinell hardness |
| Hardness, Rockwell B | 84 | 84 | Converted from Brinell hardness |
| Hardness, Vickers | 170 | 170 | Converted from Brinell hardness |
| Tensile Strength, Ultimate | 540 MPa | 78300 psi | |
| Tensile Strength, Yield | 415 MPa | 60200 psi | |
| Elongation at Break | 10% | 10% | |
| Reduction of Area | 35% | 35% | |
| Modulus of Elasticity | 200 GPa | 29000 ksi | Typical for Steel |
| Bulk Modulus | 140 GPa | 20300 ksi | Typical for Steel |
| Poisson’s Ratio | 0.29 | 0.29 | Typical for Steel |
| Machinability | 160% | 160% | Based on 100% machinability forAISI 1212 steel |
| Shear Modulus | 80 GPa | 11600 ksi | Typical for Steel |
Carbon Steel Thermal Properties
| THERMAL PROPERTIES | METRIC | ENGLISH | COMMENTS |
| CTE, linear 20°C | 11.5 µm/m-°C | 6.39 µin/in-°F | |
| CTE, linear 250°C | 12.2 µm/m-°C | 6.78 µin/in-°F | Converted from Brinell hardness |
| CTE, linear 500°C | 13.9 µm/m-°C | 7.72 µin/in-°F | Converted from Brinell hardness |
| CTE, linear 1000°C | 14.7 µm/m-°C | 8.17 µin/in-°F | Converted from Brinell hardness |
| Specific Heat Capacity | 0.472 J/g-°C | 0.113 BTU/lb-°F | |
| Thermal Conductivity | 51.9 W/m-K | 360 BTU-in/hr-ft²-°F |
Uses of Carbon Steel
Carbon steel is widely used in many industries and is classified into four types: ultra-high carbon steel, high carbon steel, medium carbon steel, and low carbon steel.
Ultra-High Carbon Steel: This kind is recognized for its toughness, but it is also extremely fragile, rendering it unsuitable for cold working. It is widely used to make hard materials like blades, huge machine parts, cutting tools, metal lamp posts, and hot water radiators.
High Carbon Steel: High carbon steel is valued for its tensile strength and adaptability. It is commonly used to manufacture cutting tools, punches, springs, high-strength wire, blades, and drill bits, making it a popular choice for a variety of applications.
Medium Carbon Steel: Medium carbon steel is relatively easy to manufacture and frequently contains tiny amounts of silicon and manganese to improve quality. It is also known as mild steel and is widely utilized in the construction of buildings and bridges. It’s also used in gears, pipes, refrigerators, automobiles, and other applications.
Low Carbon Steel: Low carbon steel is usually rolled into sheets or strips. It is commonly used in shipbuilding, automobile bodies, household appliances, and wire manufacturing. It is also used for gates, fences, railings, and a variety of other purposes.
Properties and Applications for Common Carbon Steel Grades
Carbon steel comes in a variety of forms and is used in a wide range of industries and sectors. Each grade of carbon steel—low-carbon, medium-carbon, and high-carbon—has unique applications based on its qualities.
Low-Carbon Steel:
Applications: Common applications include car body components, structural forms (such as I-beams, channel, and angle iron), pipelines, building and bridge components, and food cans.
Properties: Provides great ductility, weldability, and cost-effectiveness.
Medium-Carbon Steel:
Applications: Often used for railway tracks, train wheels, crankshafts, gears, and industrial parts. This variety is valued for its strong strength, durability, and toughness.
Properties: It strikes a balance between strength and ductility, making it ideal for long-lasting applications.
High-Carbon Steel:
Applications: Its superior wear resistance and hardness make it suitable for use in cutting tools, springs, high-strength wire, and dies.
Properties: It is highly wear resistant but less ductile, which can lead to brittleness.
Properties and Applications for Common Carbon Steel Grades
Carbon steel comes in a variety of forms and is used in a wide range of industries and sectors. Each grade of carbon steel—low-carbon, medium-carbon, and high-carbon—has unique applications based on its qualities.
| Type | AISI/ASTM name | Carbon content (%) | Tensile strength (MPa) | Yield strength (MPa) | Ductility (% elongation in 50 mm) | Applications |
| Low | 1010 | 0.1 | 325 | 180 | 28 | Automobile panels, nails, wire |
| Low | 1020 | 0.2 | 380 | 205 | 25 | Pipes, structural steel, sheet steel |
| Low | A36 | 0.29 | 400 | 220 | 23 | Structural |
| Low | A516 Grade 70 | 0.31 | 485 | 260 | 21 | Low-temperature pressure vessels |
| Medium | 1030 | 0.27 – 0.34 | 460 | 325 | 12 | Machinery parts, gears, shifts, axles, bolts |
| Medium | 1040 | 0.37 – 0.44 | 620 | 415 | 25 | Crankshafts, couplings, cold headed parts. |
| High | 1080 | 0.75 – 0.88 | 924 | 440 | 12 | Music wire |
| High | 1095 | 0.90 – 1.04 | 665 | 380 | 10 | Springs, cutting tools |
Advantages and Disadvantages of Carbon Steel
Advantages
Hardness and Strength: Carbon steel has outstanding hardness and strength, making it appropriate for a wide range of applications when compared to other materials.
Flexibility: Carbon steel’s elasticity makes it an ideal material for manufacturing machines, particularly in pressing operations and other industrial applications.
Disadvantages
Welding Challenges: Carbon steel is difficult to weld, posing a substantial difficulty for manufacturers when building parts or structures.
Brittleness: While its hardness is advantageous for cutting tools, it also makes carbon steel susceptible to breaking under stress. Carbon steel may perform less well under severe situations than specialty steels.
Conclusion
Carbon steel is a versatile and necessary material utilized in a variety of sectors due to its unique qualities and applications. From low-carbon steel, which has great ductility and weldability for structural components, to high-carbon steel, which is known for its hardness and wear resistance in cutting tools and machines, each type plays an important role in manufacturing and construction.
Understanding the various grades of carbon steel enables manufacturers and engineers to choose the best type for a given application, assuring peak performance and durability. As technology advances, carbon steel’s applications and advancements are anticipated to expand, reinforcing its role in modern industry.
Carbon steel remains a basic material in a variety of industries, including automotive and construction, energy, and manufacturing, due to its unique mix of strength, durability, and cost-effectiveness.
