Among various types of steel, carbon and stainless steel have become popular and are used worldwide. They both cater to the various needs of different sectors. But what sets carbon steel and stainless steel apart? When should you choose one steel type over the other?
This article will help you find the answer. It also guides you in choosing the right material for your projects.
Though they both have similar alloy metals, distinct properties and characteristics make them different in outcomes. Keep reading to understand the key differences between them.
Overview of Carbon Steel and Stainless Steel
Both carbon steel and stainless steel have iron as their base metal. In addition to this, they have other alloying elements to enhance properties.
As per standards, carbon steel can have up to 2.1 % carbon. Some other alloy elements include:
- Manganese (maximum 1.65%)
- Phosphorus, Silicon and Sulphur, each up to 0.5%.
Also includes some other alloying elements
- Chromium
- Cobalt
- Nickel
- Titanium
- Tungsten
- Vanadium
There is no minimum value for these elements. These are added to enhance properties. Thus, this composition makes carbon steel hard and tough to achieve high strength.
On the other hand, stainless steel is composed of a minimum 10.5% chromium in total material. It also contains nickel and molybdenum.
The presence of chromium in higher amounts makes it corrosion-resistant and stainless. It is ideal for water-based applications.
Key Differences Between Carbon Steel and Stainless Steel
Let’s explore what makes carbon steel and stainless steel unique in their characteristics.
Composition
Carbon steel focuses on high strength, while stainless steel prioritises durability and corrosion resistance.
Carbon steel is mainly composed of 96-98% iron and carbon, with additional elements including manganese, silicon and phosphorus. | Stainless steel combines iron and chromium, nickel, and other alloys to provide corrosion resistance. |
Corrosion Resistance
Corrosion occurs in materials when they react with moisture or air in the environment. This process is called oxidation, as metals react with oxygen and moisture. It is essential to prevent corrosion or rust in substances to ensure longevity.
Carbon steel is easily affected by moisture, which leads to corrosion. | Stainless steel got its name for its high corrosion resistance. It can prevent degradation caused by air and moisture. |
However, its corrosion resistance can be increased through the galvanisation process. | Here, chromium plays a main role against corrosion and rust. |
It is done by adding a layer of zinc to protect carbon steel. |
Tensile and Yield Strength
Tensile and yield strength are important aspects in the construction of bridges or heavy buildings.
Tensile strength refers to how much stress a material can bear before breaking. On the other hand, yield strength means whether a material can withstand heavy loads without bending or deforming permanently.
Carbon steel has a yield strength from 250- 800 MPa | The minimum yield strength for stainless steel is 170 MPa. It can go up to 1200 MPa if it is hardened stainless steel |
Its tensile strength varies from 450-1600 MPa | The tensile strength is generally 500 MPa, and it can reach 700 MPa maximum. |
Generally, stainless steel has good yield strength. In contrast, carbon steel has high tensile strength. But this depends on specific grades of steel.
Appearance
People with flexible budgets prioritise external appearance and quality over cost when choosing materials for their projects.
Carbon steel has a rough and uneven surface. | Stainless steel has a glossy, smooth finish. It is visually appealing. |
When it develops rusty or scaly surfaces, it doesn’t appear good.A good example is compound wall gates in our homes, which start to peel off after a few years. | Today, stainless steel is often used for staircases, window rims and gates. |
It requires coating or painting often. | It doesn’t require coating, but its cost is high |
Machining and Welding
Machining and welding properties show the nature of steel to work with.
Carbon steel can be easily machined. It is easy to cut, melt and weld. | Stainless steel needs specialised machining and welding. |
So, the process of hardening is not difficult here. | The chromium content makes it difficult to conduct heat. |
It increases the risk of bending, so the process of machining and welding becomes harder |
Heat Resistance
It indicates the material’s ability to withstand high temperatures.
Carbon steel has low heat resistance compared to stainless steel. | Stainless steel has high heat resistance. |
It begins to lose its strength when it is exposed to high temperatures around 500ºF | It can endure temperatures up to 1000ºF. |
It is an ideal material for automotive parts and aerospace industry. |
Manufacturing Process
Carbon Steel
Carbon steel is produced through a multi-step process, starting with combining iron ore, coke, and lime. First, the iron ore is extracted and processed into a usable form. Next, the iron, coke, and lime mixture are heated in a blast furnace at extremely high temperatures.
Following this, the resulting molten iron is transferred to a Basic Oxygen Furnace for further refining. Then, oxygen is blown in to remove excess carbon and impurities.
Additionally, alloying elements like manganese and silicon are added to the molten steel to enhance its properties. Then, the mixture is stirred and heated to achieve the desired chemical composition.
Finally, the molten steel is shaped using continuous casting or ingot casting, resulting in a strong and hard carbon steel product suitable for various applications.
Stainless Steel
Stainless steel is made to look smooth and shiny, even manufactured from scratch. To start, tons of metals, including iron, chromium, nickel, and others, are combined.
These metals are then heated to ensure added strength and rust-proofing. After several hours, the metals start to melt at high temperatures. The molten metal is transferred to a refining furnace to remove impurities.
Argon and oxygen gas are passed through pipes to remove impurities. It causes them to float to the surface for removal. Finally, the refined mixture flows out of the furnace and is cast into a long mould. The result is a long ribbon of steel, which is later cut into slabs.
Applications
Carbon Steel
- Its hardness makes it ideal for heavy construction projects, bridge components and other marine structures.
- It is also used in railway tracks as it can endure high vibrations and shocks.
- Carbon steel is ideal for making sharp-edge tools and cutting tools, as it makes them hard and durable.
Stainless Steel
- Stainless steel parts are used widely in vehicle parts, such as engines, gears, and exhaust systems, due to their high heat resistance and low maintenance.
- Its use extends even to aerospace applications, as it has low maintenance and fewer repair needs.
- Stainless steel plays a vital role in places where hygiene is needed. We can see many stainless-steel equipment made from it as doctor’s tools. It remains clean without any chemical reactions.
- One of the common uses of stainless steel is as kitchen utensils. It gives a glossy finish, durability, and overall health benefits to use stainless steel in kitchens through cutlery or utensils.
- Nowadays, it is used in staircases and gates for an aesthetic appearance and easy maintenance.
Advantages of Carbon Steel
- Incredibly strong and highly resistant to wear and tear. Hence, ideal for heavy-duty projects.
- Considered affordable and fit within budget.
- Can be used in various industries, construction projects, and tool-making.
- Has high tolerance to shocks and vibrations.
- Can be recycled easily and machined and welded quickly.
Disadvantages of Carbon Steel
- Sometimes less malleable in nature due to high carbon content.
- Vulnerable to moisture, leading to corrosion.
- Has a rough finish and an unattractive appearance.
Advantages of Stainless Steel
- The best feature is that it acts well against corrosive situations.
- Can resist high temperatures.
- Low long-term costs.
- Gives a smooth and shiny appearance.
Disadvantages of Stainless Steel
- High setup costs.
- Challenging manufacturing process, leading to high material waste.
- Requires well-trained labourers and specialised equipment.
How to Choose the Right Steel for Your Project
The key differences, advantages, and disadvantages of carbon and stainless steel have been explained above. Now you can easily choose the right steel type for your projects. Here are a few steps regarding steel type selection:
- Understand your project purpose: You should be clear about your objectives. Consider factors such as project type (residential, commercial or industrial), environmental factors, and design requirements.
- Strength: Calculate the strength required for the construction. If high yield strength and tensile strength are needed, choose carbon steel.
- Corrosion Resistance: This depends on environmental conditions and the client’s wishes. If regular checks and maintenance are not feasible, opt for stainless steel.
- Budget: Above all, budget matters. If you have a high budget, you can select stainless steel for construction projects like gates, grills, and staircases.
- Consult with suppliers or project makers: It is always advisable to get support from reliable project experts to choose the right metal for your project.
Conclusion
The choice between carbon steel and stainless steel is based on the requirements of your project. By understanding the key differences of each material, it is easy to make informed decisions. By consulting with experienced project makers and suppliers, you can ensure the success of your project.
FAQs
Stainless steel is suitable for outdoor uses. It can resist harsh environments, heavy rain and high humidity.
Consider factors like strength, corrosion resistance, budget, and usage needs. Consult experts if needed.
Yes, but it needs more caution and specialised techniques. It needs fillers to prevent damage and ensure strong joints.