What is Mild Steel? Properties, Grades & Uses

Mild steel is affordable, strong, and offers easy fabrication, making it a common material for metal fabrication services. If you’re still asking yourself the question ‘What is mild steel?’ – we’re here to help answer it. 

In our blog below, we’ll dive into more detail regarding the material’s grades and typical applications, as well as the properties of mild steel. 

What exactly is mild steel?

Mild steel is a ferrous metal made from a combination of iron and carbon – amounting to around 0.05% – 0.25%, making it known as a low-carbon steel. 

As a result of this low carbon content, mild steel is more ductile and malleable, making it easier to work with when compared to higher carbon steels. 

What are the properties of mild steel?

Mild steel has several properties associated with it – making it an affordable and versatile choice for those working in metal fabrication, welding, and powder coating services. Let’s explore some more below in more detail. 

Chemical composition

As mentioned, carbon content is usually between 0.05% and 0.25%, which is considered low. 

The rest of this material’s composition is mostly iron, with potential traces of other elements such as manganese, silicon, and phosphorus.

Mechanical properties

Mild steel has a moderate tensile strength, typically around 400-550 MPa (megapascals). This makes it strong enough for some structural applications, but higher carbon steels are still a much stronger option. 

It’s also highly ductile and malleable too. So it can be stretched, rolled, and bent, as well as being able to withstand sheet metal folding and be shaped into various forms without breaking. This type of steel can absorb impact and shock well, making it durable under heavy loads or stress. It can also be hardened through heat treatment processes like case hardening.

Thermal properties

The melting point of mild steel is around 1,425 to 1,505°C. 

It offers good thermal conductivity, making it suitable for heat exchanging applications.

Weldability

All of the different types of welding (including MIG, TIG, and spot welding) work well with mild steel, due to its low carbon content. 

It typically does not require any special processes or equipment to undergo welding services.

Highly magnetic

Mild steel is highly magnetic due to its high iron content. 

This is one reason why it’s commonly used in the motor industry and in other electrical equipment.

Low corrosion resistance

One of the downfalls of mild steel is that it is highly susceptible to corrosion and rusting when exposed to moisture and air. 

This is unless it is painted or powder coated. Powder coating services provide a hard wearing, water resistant finish that is not vulnerable to damage from chemicals or UV light. Find out more with our ultimate guide to powder coating.

Machinability

Mild steel is relatively easy to machine and fabricate using industrial methods such as laser cutting, drilling, and turning.

Mild steel grades

Mild steel is commonly classified under British and European standards – otherwise known as Eurocodes or structural steel design standards. These common mild steel grades are used in various industries depending on the required mechanical properties. 

Let’s take a look at some mild steel grades in more detail. 

Mild steel grade | EN 1.0038 / S235JR (EN)

Carbon content (approx):

0.12% to 0.20%

Properties:

Good machinability and moderate strength.

Typical applications:

Structural work in buildings, bridges, and general construction.

Mild steel grade | EN 1.0038 / S235JR (EN) / BS EN 10025

Carbon content (Approx):

0.25%

Properties:

Higher strength than S235JR. Good ductility.

Typical applications:

Large-scale projects like bridges and offshore structures.

Mild steel grade | EN 1.0044 / S355JR / BS 4360 (50B)

Carbon content (approx):

0.23%

Properties:

Good tensile strength and toughness. Better wear resistance.

Typical applications:

Demanding structural projects like heavy machinery or crane booms.

Mild steel grade | EN 1.0301 / DC01 (EN 10130) / BS EN 10130

Carbon content (approx):

0.12%

Properties:

Excellent surface quality with good weldability and ductility.

Typical applications:

Manufacturing processes like automotive body parts and appliances.

Mild steel grade | EN 1.0402 / C22 (EN) / BS 970 070M20

Carbon content (approx):

0.18% to 0.23%

Properties:

Moderate strength, good machinability, and weldability.

Typical applications:

Less demanding parts like shafts, gears, and other automotive parts.

Mild steel grade | EN 1.0503 / C45 (EN) / BS 970 080M46

Carbon content (approx):

0.42% to 0.50%

Properties:

Higher strength with reduced weldability and machinability.

Typical applications:

Stronger components like axles, gears, and crankshafts.

Mild steel grade | EN 1.1121 / 080A15 (EN) / BS 970

Carbon content (approx):

0.13% to 0.18%

Properties:

Good weldability, machinability, and toughness.

Typical applications:

General engineering and light fabrication work.

What is mild steel used for?

There are several different projects and processes in which mild steel is used. For example, in:

Construction and structural applications

Mild steel is widely used in the construction of buildings, bridges, and other infrastructure to create components such as beams, columns and frames. 

This is due to its high strength and ability to bear heavy loads. It can also be found in reinforced concrete structures as it is used to strengthen the structure and prevent cracking.

Automotive and transportation industry

Mild steel is a common material in the automotive and transportation industries. There are many parts of a vehicle that are often made from mild steel because it is easily formed and welded. This includes:

• Body panels
• Chassis and frames
• Engine parts, such as brackets and supports
• Interior decorations

It’s also widely used on our railways, and to create certain components of train bodies and undercarriage structures too.

Engineering and fabrication

Due to its excellent weldability, mild steel is used for fabricating metal structures, such as bridges, platforms, and frameworks. 

It’s also used to create fasteners like nuts, bolts, and screws.

Machinery and equipment

Mild steel is a common material found in many areas of the agricultural sector. It is used to make parts for tractors, ploughs, and many other forms of farming machinery due to its durability and ability to handle heavy loads. 

It’s also used to fabricate components for industrial machinery like conveyors, gears, and shafts.

Household appliances

Last but not least, mild steel is also used…within your home! A lot of the white goods in your household, such as your refrigerator or washing machine, will contain mild steel components. 

It’s also commonly used in the production of metal furniture, like shelving units and bed frames. This is mainly due to the material’s durability and affordability.

Mild steel and metal fabrication services

Here at Salamander Fabrications, the experienced team that runs our sheet metal fabrication services understands exactly what mild steel is and what to do with it. 

Our experts have a wealth of experience and the skills required to turn your product or project ideas into reality.

To do so we may employ a number of techniques, including:

• Sheet metal folding (sometimes known as CNC press braking)
• Welding
• Laser cutting
• Punching
• CAD design (we use SOLIDWORKS)
• Powder coating and finishing

If you would like some more information or advice about our ISO-accredited services please feel free to contact us, give us a call on 01484 843599, or send an email to sales@salamanderfabs.com.