Carbon Steel Vs Mild Steel: Definition, Types, Differences, Manufacturing Processes, And Use

Carbon steel and mild steel often confuse many people, not only for ordinary people, but also for non-professionals to tell the difference between them. As a worker engaged in steel pipe production, I will deeply discuss the definition, advantages, disadvantages, types, differences, manufacturing process and application of carbon steel and mild steel. I believe you will have a more comprehensive understanding of these two kinds of steel after reading this article.

First of all, let's take a look at the definitions and advantages and disadvantages of mild steel and carbon steel.

What Is Mild Steel?

Soft steel refers to carbon steel with a low carbon content (usually below 0.25% carbon content). Soft steel, also known as "low-carbon steel", is a category of carbon steel.

Advantages Of Mild Steel

Excellent Machinability

Because of its low carbon content, low carbon steel has excellent weldability and processability, as well as good plasticity and toughness.

This makes low carbon steel an important material for manufacturing all kinds of mechanical parts and structures.

Better Malleability

Mild steel can show good ductility and achieve good plastic deformation under stress.

This makes mild steel particularly suitable for processes such as bending.

Low carbon content makes low-carbon steel more malleable and easier to form, shape and weld than other types of steel.

Low carbon steel has good mechanical machinability and can be drilled, cut and machined into various shapes and sizes.

Low Cost

Compared to other steels, the price of soft steel is relatively low, which is also an important factor for its widespread application in multiple industries. Soft steel is considered a relatively inexpensive and versatile material. In fact, over 85% of the structural steel pipes produced by Yuantai Derun are soft steel pipe products. These steel pipes are commonly used in various construction and manufacturing industries.

In addition, compared with other materials, such as aluminum and copper, low carbon alloy has relatively high tensile strength, making it suitable for high application applications such as beams, columns and mechanical parts.

Its versatility and experience make it a popular choice for all applications.

Disadvantages Of Mild Steel

Lower Tensile Strength And Fatigue Strength

Compared with medium carbon steel or high carbon steel, the tensile strength and fatigue strength of mild steel are not good enough, which means that mild steel is more prone to fracture or failure under high load or long-term cyclic load.

Insufficient Hardness

Compared with spring steel, mild steel has lower restoring force and hardness.

This makes mild steel less suitable for applications that require high resilience and elasticity, such as spring manufacturing.

What Is Carbon Steel?

Carbon steel, also known as carbon steel or plain carbon steel, refers to an iron-carbon alloy with a carbon content of 0.0218% to 2.11%.

It also contains a small amount of silicon, manganese, sulfur, phosphorus and other elements.

Carbons can be further divided into various brands according to their chemical composition and mechanical properties, such as soft carbon (low carbon), medium carbon, high carbon and ultra-high carbon.

Each level has its own specific purpose and application, and the performance depends on the performance of the most expensive product.

Let's take a look at the advantages and disadvantages of carbon steel.

Advantages Of Carbon Steel

High strength: carbon steel has high strength and hardness, which makes it perform well in many applications that require heavy load or high pressure.

Low cost: compared with other alloy steels and stainless steels, carbon steel is cheaper to produce because it does not require expensive alloying elements.

Good machinability: carbon steel is easily machined by cutting, bending, welding and forging, which makes it an ideal material for manufacturing a variety of components and structures.

Wide range of applications: carbon steel is suitable for a variety of application scenarios, including buildings, bridges, mechanical parts, automotive parts, ships and pipelines.

Good wear resistance: carbon steel has high surface hardness and good wear resistance, which is suitable for situations that need to bear wear.

Disadvantages Of Carbon Steel

Easy to rust: carbon steel reacts easily with water and oxygen, resulting in rust and corrosion.

This limits its use in wet or corrosive environments.

Poor toughness: compared with some alloy steels, carbon steel has lower toughness, that is, it is more likely to fracture or crack under impact.

Poor thermal stability: the strength and hardness of carbon steel will decrease at high temperature, which limits its use in high temperature environment.

Poor weldability: some carbon steels with high carbon content are prone to crack and deformation during welding, so special welding processes and measures are needed.

Sensitivity to the environment: the properties of carbon steel may be affected by environmental factors, such as temperature, humidity and corrosive media.

Carbon Steel Type

There are many types of carbon steel, each of which has unique performance and application.These types include:

Low Carbon Steel

Carbon steel with less than 0.25% carbon content has lower strength and hardness, but good plasticity and toughness, and good ductility. It is usually used to manufacture stamping parts, weldments and carburized parts, such as machine housings, chains, bushings, bolts, nuts, tubing, gaskets, containers and so on.

Low carbon steel is also widely used as carbon steel billet of carburized steel.

Medium Carbon Steel

Carbon steel with a carbon content of 0.25% to 0.60% has medium strength and hardness, moderate plasticity and toughness, and is usually used to manufacture mechanical parts under medium load and medium speed working conditions. such as automobile variable speed gears, machine tool gears, worms, spline shafts and so on.

High Carbon Steel

Carbon steel with carbon content more than 0.60% has high strength and hardness, but poor plasticity and toughness. It is usually used to manufacture springs, wire ropes, rolls, wire drawing dies, cutting tools and other parts that require high hardness and wear resistance.

Medium and high carbon compounds are commonly used in the manufacture of mechanical components, such as moulds, bends and moulds.

Its high strength and especially high hardness make it an ideal choice for all kinds of moulds.

What Is The Difference?

Name	Mild Steel	Carbon Steel
Carbon Content	Low（<0.25%）	Medium to Ultra-High(0.12%<C<2.0%)
Hardness	Low	Low to Ultra-High
Mechanical Strength	Moderate	High
Ductility	High	Moderate – Low
Corrosion resistance	Poor	Poor
Weldability	Good	Generally not suitable
Cost	Inexpensive	Slightly higher per weight
Wear resistance	Poor	Low to high
Machinability	High	Comparison of Low between medium carbon steel and high carbon steel

Manufacturing Process Of Mild Steel And Carbon Steel

The manufacturing process of low-carbon carbon and carbon carbon will be different according to the quality requirements of the most expensive products and the most expensive products.

In general, the manufacturing process can be divided into three stages:

1. Primary processes

2. Secondary processes

3. Casting

Primary Processes

Steel can be made from recycled or recycled and virgin steel using the BOF process.

Basic Oxygen Furnace (BOF)

Mild and carbon steel are made using the basic oxygen furnace (BOF) method. This turns raw materials like iron ore and coke into liquid steel. The liquid steel is poured into molds to make slabs or ingots. Pure oxygen is pushed through the liquid steel to remove extra carbon, making the finished product have up to 0.5% carbon.

Secondary Processes

Market demand for higher quality steel products with more consistent properties has driven the development of secondary steelmaking processes. This enables manufacturers to produce mild, medium, high or ultra-high carbon steels by adjusting the carbon content. As a reminder, it is from this secondary steelmaking process that mild steel is produced.

Electric Arc Furnace (EAF）

In an electric arc furnace, the composition of steel can be changed by adding or removing specific components or controlling temperature. The electric arc furnace process includes:

Stirring - Mixing well and removing impurities to ensure the steel has a consistent composition. Ladle furnace - Controls temperature precisely and adds alloys accurately. Ladle injection - Using inert gas at the base of the steel to mix it thoroughly. Degassing - Eliminates hydrogen, oxygen, and nitrogen, and reduces sulfur in the steel. Composition adjustment - Essential for proper mixing using sealed argon bubbling and oxygen blowing (CAS-OB).

Deoxidizing Steel

Oxygen removal is a crucial step in secondary steelmaking. As the steel begins to solidify, oxygen reacts with carbon to produce carbon monoxide gas.

Controlling deoxidation changes the properties of steel and makes it suitable for different applications. Deoxidizing steel processes:

Rimming steels are non-deoxidized or partially deoxidized steels.

Capped steels are initially comparable to rimming steels, but the mold is capped to prevent the creation of carbon monoxide.

Semi-killed steels are partially deoxidized and have a carbon content in the range of 0.15–0.3%.

Killed steels are totally deoxidized to the point where no carbon monoxide is produced during solidification.

Casting

Traditional casting uses rail cars with molds filled with molten steel. Casting machines can make shapes of molten steel that are better for processing.

Ingots go to soaking pits to be reheated for hot rolling. In a continuous casting machine, steel is produced into slabs, blooms, or billets.

Finishing Processes Of Mild Steel And Carbon Steel

How steel is finished affects how it looks and how well it works. Carbon steel is finished using:

1.Rolling

2.Heat treatment

3.Surface treatment

4.Downstream secondary processing

Rolling

Product Rolling

Solid ingots must be rolled into more user-friendly shapes and sizes, similar to continuous ingots.

When steel enters the machine, the rotation speed of the rolling mill is faster than that of the steel, pushing the steel forward and compressing it.

Hot Forming

To break up the steel's original structure, it is heated above the point where it can be re-shaped. This makes the grains in the steel more even and the carbon more evenly distributed.

Cold Forming

Cold forming is carried out at lower temperatures. This process makes the metal stronger and improves the surface finish. In a rolling mill, semi-finished materials are processed into intermediate products. They are ready for other industries to manufacture and process.

Heat Treatment

Heat treating steel changes its mechanical properties. It makes steel more ductile but less hard and strong.

Normalizing

Steel is heated to 40~60 °C over its upper critical temperature. This makes it stronger and harder.

Annealing

The steel is heated to the solid solution temperature for one hour and then cooled at a rate of 21 degrees Celsius (70 degrees Fahrenheit) per hour. Eliminated internal tension and produced soft and ductile steel.

Quenching

This is similar to normalizing heat treatment, except that cooling is accelerated by quenching in water, salt water, or oil. The resulting material is very hard but very brittle, easily broken and broken.

To control steel properties, it is cooled slowly to room temperature. This is called tempering.

Surface Treatment

About one-third of all steel is coated to prevent corrosion and make it easier to paint.

Hot Dip Galvanizing

The first step in the hot-dip galvanising process is to pickle the steel fabricated parts. This removes the iron oxide from the surface of the steel fabricated parts. Once pickling is complete, the parts are cleaned using an aqueous solution of ammonium chloride or zinc chloride. This is followed by immersion in a tank containing a solution of ammonium chloride and zinc chloride. Finally, the parts are sent to a hot-dip galvanising tank. Hot-dip galvanising offers several advantages, including uniform coating, strong adhesion and a long service life.

Electrolytic Galvanizing

Another method for depositing a zinc layer on steel is through the use of an electrolyte solution and an electric current. This enables more precise control of the coating thickness.

Galvanised Aluminium-magnesium Coating

This process is the surface treatment technology also used by Yuantai Derun Zinc Aluminium Magnesium Steel Pipe, by adjusting the proportion of zinc aluminium magnesium mixed liquid, it will be plated on the steel plate or steel workpiece, in order to achieve the purpose of improving the corrosion resistance of zinc aluminium magnesium steel pipe.

Downstream Secondary Processing

Downstream companies further process the raw steel into the desired finished product. This includes welding methods such as ERW, LSAW, SSAW, cutting, bending, perforating, polishing, deburring, and various other processing steps such as machining and joining, often using machine tools to uniformly remove the surface metal and perform welding.

Use

Application	Carbon Steel	Mild Steel(Low Carbon Steel)
1	Engine parts	building structure
2	wheel	Support frame
3	Automotive components	steel beam
5	tool	furniture
6	knife	doors and windows
7	mechanical equipment	Small steel groove
8	aerospace	steel pipe
9	Electronic devices	Steel strip or steel plate
10	bearing	Agricultural machinery
11	mould	Car cab, engine hood
12	lathe	Mechanical parts with low strength requirements

Does Carbon Steel Rust Easily?

Carbon steel is made primarily of an iron-carbon alloy, which makes it more susceptible to rust.

When exposed to humid conditions, carbon steel can corrode, reacting with oxygen in the air to produce rust, a reddish-brown iron oxide that, over time, will also fall off as slag.

Rust is also a common problem for mild steel. Unless we apply surface treatment to carbon steel, such as galvanising, painting, etc..

The rate of corrosion of carbon steel may be affected by the environment in which it is used, the temperature, and so on.

The use of coatings such as paint or plating on carbon steel can help reduce the risk of rusting.

Is Carbon Steel Better Than Mild Steel?

There are several scenarios for this question. The two types of carbon steel have different properties and are suitable for different purposes. Which one is better depends on your immediate needs.

Mild steel is better suited for low-stress applications because it is easy to work with and inexpensive. Carbon steel is better for high-stress applications because it is made of high-carbon steel and is strong.

Medium and high carbon steels are expensive. They are not convenient for large-scale use.

Carbon steel is harder to weld than mild steel, but that doesn't mean it can't be welded.

Yuantai Derun Steel Pipe Group

Yuantai Derun is the world's largest supplier of square tube and pipe with 100 structural steel pipe production lines in China.

We are the square tube experts and have been providing quality customer service and products since 2002.

At Yuantai Derun, we offer a wide variety of structural steel tubes and steel profiles for a variety of applications.

Our inventory includes: square steel tubing, rectangular steel tubing, round steel tubing, galvanized steel tubing, ERW steel tubing, LSAW steel tubing, zinc-aluminum-magnesium steel tubing, spiral-welded tubing, and steel profiles.

We stock a wide range of products including: tubes, profiles and plates.

We can cut steel pipe and steel lengths to your specific requirements.

Today, we welcome steel pipe users from all walks of life around the world to inquire, order and visit our factory or online.

FAQ:

1.What is the difference between cs and ms?

Carbon steel is a type of alloy steel that consists primarily of carbon and iron and contains small amounts of other elements. Mild steel is a type of carbon steel with a lower carbon content, usually between 0.05% and 0.25%. In comparison, plain carbon steel has a carbon content of between 0.30% and 2.0%. Mild steel typically has good weldability, workability, and ductility, while carbon steels (especially medium and high carbon steels) may have higher strength and hardness.

2.What is the difference between MS CS and SS?

The difference between MS (Mild Steel), CS (Carbon Steel), and SS (Stainless Steel) lies in their composition and properties.

Mild Steel (MS): Contains a low carbon content, making it less hard and more ductile. It is often used in construction, automotive, and machinery.

Carbon Steel (CS): Generally refers to steels with higher carbon content than mild steel, providing increased strength and hardness. Commonly used in structural applications, pipelines, and machinery.

Stainless Steel (SS): Contains chromium and nickel, making it resistant to corrosion and staining. Often used in kitchenware, appliances, and medical equipment.

3.How to tell high carbon steel from mild steel?

By observing the composition and properties of high carbon steel, it is possible to distinguish between high carbon steel and soft steel:

High carbon steel: contains a large amount of carbon, making it harder and more brittle. It is often used for tools and blades.

Soft steel: With a lower carbon content, it is softer and more resilient. It is commonly used in construction, machinery, and automotive applications. You can also use a simple test, such as a file test - compared to soft steel, high carbon steel is more difficult to file.

4.What are the disadvantages of carbon steel?

Corrosion: Carbon steel rusts and corrodes when exposed to moisture or harsh environments.

Brittleness: High carbon steel can crack under stress or impact.

Maintenance: Regular maintenance is needed to prevent rusting and deterioration.

Weight: Carbon steel is heavier than other materials, limiting its use in certain applications.

Reactivity: Carbon steel can react with certain chemicals or environments, causing damage or degradation.