Steel is a commonly used engineering material. It has many uses, from construction to industries and aerospace to even kitchenware. There are many types of steel. They have different properties for various needs. Among those carbon steels are standard, cheap and have various properties.
This blog will explain further about carbon steels, their types, and applications. Keep reading.
What is Carbon Steel
Like other steels, carbon steel also has iron as its base metal. But it contains up to 2.06% carbon as an alloy. It also has other elements
Manganese – up to 1.6 %
Sulphur- typically below 0.05% to avoid brittleness, although some lower-quality grades may reach up to 0.5%
Silicon – 0.5 %
Phosphorus – 0.5 %
However, the carbon content determines the strength and ductility of steel. If it is present in a higher amount, it becomes harder but less ductile. Low-carbon steels are usually flexible and easy to stretch.
Types of Carbon Steel
Carbon steels are usually classified into three categories based on the presence of carbon content such as:
Low-Carbon Steel
- Carbon content-0.05-0.3%.
- It is also known as mild carbon steel. Due to their low carbon amount, they are very ductile. This makes them easy to melt, weld, and work with.
- Additionally, they are highly flexible, allowing for easy stretching.
- Low-carbon steel is commonly used in wires, machine parts, and sheets. It has lower production costs.
Medium-Carbon Steel
- Carbon content: 0.3-0.6 %
- Though it has a slightly higher carbon content, it is relatively stronger and resistant to wear.
- It can offer a balance between ductility and hardness.
- It can be heated to increase its properties.
- It is commonly used in the production of axles, gears, engine parts, and machine components.
High-Carbon Steel
- Carbon content: 0.6-1.0% It is the highest grade of carbon steel.
- It is harder but less malleable in nature.
- Due to its hardness, it is commonly used in cutting tools, high-strength wires, springs, and other tools.
Manufacturing of Carbon Steel
Iron ores are extracted from natural deposits to produce carbon steel. It is then combined with coke (a special coal) and limestone. Next, these ingredients are heated in a blast furnace at 1200-1400 º C.
During heating, the coke’s carbon dissolves into the molten iron, increasing its carbon content.
This produces pig iron, which is rich in carbon. The remaining impurities then form slag with the limestone and rise to the surface for removal.
Afterwards, the carbon amount is reduced to the desired level through further refining. Finally, the material undergoes casting, rolling, and heat treatment to become carbon steel.
Properties of Carbon Steel
Here is a list of different properties of carbon steel along with their specifications.
| Properties | Definition | Specifications | |
Physical Properties | Density | It indicates how much mass is packed into a given volume of the material. | 7.7-7.9 g/cm3 |
Mechanical Properties | Hardness | Measures the material’s surface resistance to wear and scratches. | 125-580 Brinell |
| Yield Strength | Measures the stress point at which material flexibility ends and permanent bending begins. | 250-800 MPa | |
| Ultimate Tensile Strength | Maximum load a material can handle before completely failing. | 450-1600 MPa | |
| Elastic Modulus | It shows how stiff and firm the material is. It shows the ability to prevent deformation when facing stress. It influences the structural integrity of carbon steel. | 190-210 GPa | |
| Poisson’s Ratio | It refers to how the width of a carbon steel changes when subjected to vertical pressure. It shows the ability to stretch and compress. | 0.28-0.30 | |
| Shear Modulus | Measures the shear stiffness or resistance to deformation under shear stress. | 72-80 GPa | |
| Thermal Properties | Thermal Expansion | It describes how materials respond to various temperature conditions. | 11-16.6 µm/m.K |
Melting Point | It refers to a temperature point at which a material changes from solid to liquid. It is helpful for welding and joining processes. | 1450-1550 ºC | |
| Thermal Conductivity | Ability of a material to conduct heat. | 24.5-65.2 W/m-K | |
| Specific Heat | Energy needed to raise the temperature of 1 unit mass by 1 degree. | 0.470-0.519 J/g-ºC | |
| Electrical Properties | Electrical Resistivity | It measures the opposition to the flow of electric current through a material. | 0.213 µΩ/m(at 70º C) |
The values provided here are approximate only. It can vary based on carbon content, manufacturing process and materials used.
Uses and Application of Carbon Steel
Carbon steel has a wide range of applications due to its overall good performance. Some of these applications are explained below.
Construction
Carbon steel and concrete are used widely in the construction sector for reinforcement. They are less expensive yet strong and durable.
Beams and columns in bridges are made with carbon steel due to its high resistance to wear and tear. Moreover, carbon steels can withstand heavy stress, making them ideal for high-load carrying projects.
Automotive Parts
Most automotive parts utilise carbon steel in production. Starting from gears, engines, shafts, and other parts, it is highly suitable for toughness and resistance. It is cost-effective in the production of vehicles.
Cutlery and Knives
Carbon steels can be heat-treated and forged. It makes them ideal for making cutlery and knives. It provides hardness, sharpness, and edge perfection. Moreover, it is affordable to make knives in carbon steel compared to other steel types.
Tools
Drills, saws, and hammers require toughness and hardness. Carbon steel provides these properties and helps maintain sharp edges. It can produce durable tools that can withstand heavy wear and tear.
Carbon Steel vs. Other Types of Steel
| Carbon Steel | Stainless Steel | Alloy Steel | Tool Steel |
Carbon steel has a high amount of carbon up to 2% | Stainless steel has significant chromium as its major alloy, making it distinct. | Alloy steel contains varying amounts of different alloys along with base metal. | Tool steel has high amounts of tungsten, molybdenum, and vanadium. |
Offers hardness and strength. | Prioritises corrosion resistance above all. | Gives a balance between strength, hardness, and corrosion resistance. | Tool steel, extremely hard and highly resistant to wear and tear. |
Used in various structural and mechanical applications due to its strength and affordability, including:- Construction – Automotive – Bridges – Shipbuilding – Machinery – Railway tracks | Utilised in corrosive environments and in hygienic needs such as:- Kitchenware – Medical equipment – Food processing – Chemical and pharmaceutical industries – Aerospace – Decorative elements | Commonly used in- Aerospace – Power generation – Chemical processing – Oil and gas drilling – Heavy machinery | Due to its extreme hardness and wear resistance, it is used in:- Cutting tools – Dies and moulds – Machine tooling – Wear-resistant parts |
| Carbon steel is cheap because it involves simple composition and production. | Stainless steel is expensive because it has properties of corrosion resistance and high strength. The presence of chromium makes it pricey. | Alloy steel is moderately high in price due to the various alloying elements. | Tool steel is the most expensive because it involves complex production. It has a higher production cost due to the use of rare alloy elements. |
| Strongly attracted to magnets | Some are magnetic, some grades are non-magnetic | Generally magnetic | Highly magnetic |
Advantages of Carbon Steel
- Carbon steel has high strength and durability.
- It can be heat-treated, easily weldable, and made into desired shapes.
- Carbon steel is more budget-friendly when compared to other steel types.
- It is used in many fields including construction, industries, cars production, and machinery.
- Carbon steel can be easily produced and is accessible worldwide.
- It is resistant to heavy vibrations and stresses.
Disadvantages of Carbon Steel
- Carbon steel rusts easily in moist or airy environments.
- High temperatures can weaken and warp carbon steel.
- The more carbon in carbon steel, the more likely it is to crack under stress.
- Regular maintenance, coatings, and painting help protect and preserve carbon steel
Conclusion
To conclude, carbon steel is a reliable material with many uses. Its strength and affordability make it a popular choice across industries. While it has some limitations, selecting the right grade ensures optimal performance.
FAQs
Carbon steel is stronger and cheaper but rusts easily. While stainless steel resists corrosion and is ideal for wet environments.
Yes, carbon steel is strongly attracted to magnets. So, it is useful for magnetic applications.
Yes, if it is galvanised. This process involves coating of the carbon steel with a layer of zinc.