Mild steel is a foundation block of modern industry as it is affordable and can be used in many ways. Whether you work in construction, manufacturing or the automotive industry, it is important to know about this metal. This guide covers its important features, common uses and the benefits it can bring to your business.
What Is Mild Steel?
Mild steel is a type of carbon steel with a low carbon content of between 0.05% and 0.25%. This material is very flexible, can be welded and is easy to machine. It is one of the most common and widely used metals in the world because it is strong and affordable at the same time.
Key Features & Properties of Mild Steel
To get the most out of mild steel, you need to know what makes it different from other types of steel.
Physical Properties
Mild steel is magnetic because it has high iron content that is important for electrical and magnetic uses. It has good thermal conductivity so heat can move quickly through it. Its density is about 7.85 g/cm³ which gives it enough weight for structural stability without being too heavy to handle and install for large scale construction.
Mechanical Properties
Mild steel can handle a lot of stress before it bends or breaks because of its high tensile strength and ductility. This toughness makes it useful for structural parts that need to hold heavy loads. It isn’t as hard as high carbon steels, but its mix of strength and flexibility makes it less likely to break.
Advantages in Fabrication
One of the best things about mild steel is how easy it is to work with. It is easy to weld, cut and machine which speeds up production and lowers the cost of making things. This ease of forming lets you make complicated designs without sacrificing the strength of the structure.
Limitations
The main problem with mild steel is that it is not well resistant to corrosion. It rusts when it comes into contact with water and air which can weaken its structure. Because of this, you need to take extra steps like painting, galvanizing or powder coating to protect the product.
Cost/Value Proposition
Mild steel is one of the most affordable metals that has a very good strength-to-cost ratio. Its low initial cost, along with its long life and ease of production, makes it cheap to own. This financial benefit lets you keep the quality of your work while still being able to manage project budgets well.
Sustainability and Recyclability Aspects
Mild steel is a material that can be recycled many times which helps you reach your ESG goals. It can be melted down and used again and again without losing its properties. This closed loop lifecycle cuts down on waste and the need for new resources and makes your final products better for the environment.
Mild Steel Grades & Types
Comparing Common Carbon Steel Grades
This table will help you see how some of the most common grades of mild steel stack up against each other according to different standards. This makes it easier for you to pick the right type for your needs.
Carbon Steel Grade Equivalents Table
| USA (ASTM/SAE) | Europe (EN) | Germany (DIN) | Italy (UNI) | France (NF) | Japan (JIS) | China (GB/T) |
|---|---|---|---|---|---|---|
| A36 | S235JR | St37-2 | FE360B | E24-2 | SS400 / SM400A | Q235B |
| A283 Gr. C | S235JR | St37-2 | FE360B | E24-2 | SS400 | Q235B |
| A516 Gr. 60 | P265GH | HII | FE410-1KW | A42CP | SGV42 | Q245R |
| A516 Gr. 70 | P355GH | 19Mn6 | FE510-1KW | A52CP | SGV49 / SPV355 | Q345R |
| A572 Gr. 50 | S355J2+N | St52-3N | FE510D | E36-3 | SM490C | Q345B |
| SAE 1008 | DC01 / C10E | St12 / CK10 | FEP01 / C10 | – | SPCC / S10C | – |
| SAE 1010 | C10E | CK10 | C10 | – | S10C | 10# |
| SAE 1018 / 1020 | C20E / S275JR | CK20 / St44-2 | C20 / FE430B | E28-2 | S20C | 20# |
| SAE 1035 | C35E | CK35 | C35 | XC38 | S35C | 35# |
| SAE 1045 | C45E | CK45 | C45 | XC48 | S45C | 45# |
Sources:
Steel Equivalent Grades | ASTM/ UNS/ DIN
Steel Grades Equivalency Chart
Keep in mind:
These equivalents are just for reference. Before you make your final choice, you should always double-check the chemical and mechanical properties.
International Standards for Mild Steel
Knowing these things will help you make sure that the steel you have is right for your project.
| Standard Number | What It Covers |
| ASTM A36 / A36M | Standard specification for carbon structural steel shapes, plates, and bars |
| ASTM A283 / A283M | Low and intermediate tensile strength carbon steel plates |
| ASTM A529 / A529M | High-strength carbon-manganese steel shapes |
| ASTM A572 / A572M | High-strength low-alloy columbium-vanadium structural steel |
| ASTM A106 / A106M | Seamless carbon steel pipe for high-temperature service |
| ASTM A105 | Forged carbon steel piping components for ambient- and high-temperature service |
| EN 10025-2 | Non-alloy structural steels (e.g., S235JR, S275JR, S355JR) |
| EN 10210-1 | Hot finished structural hollow sections of non-alloy and fine grain steels |
Chemical Composition of Common US Mild Steels
To better understand if your steel can be used in your application, you should know what it’s made of. Here are the basic chemical compositions for two important US grades.
| ASTM A36 | ASTM A106 Gr B | AISI 1005 | AISI 1010 | AISI 1020 | AISI 1025 | |
| Carbon (max %) | 0.25–0.29 | 0.30 | 0.06 | 0.08–0.13 | 0.18–0.23 | 0.22–0.28 |
| Manganese (%) | ~1.03 | 0.29–1.06 | 0.25–0.40 | 0.30–0.60 | 0.30–0.60 | 0.30–0.60 |
| Phosphorus (max %) | 0.04 | 0.035 | 0.04 | 0.04 | 0.04 | 0.04 |
| Sulfur (max %) | 0.05 | 0.035 | 0.05 | 0.05 | 0.05 | 0.05 |
| Silicon (%) | ≤0.28 | ≥0.10 | 0.10 | 0.10 | 0.10 | 0.10 |
| Iron (Fe) (%) | 98–99 | 98–99 | Balance | Balance | Balance | Balance |
| Tensile Strength (MPa) | 400–550 | ≥415 | 305–450 | 350–470 | 420–550 | 430–560 |
| Yield Strength (MPa) | ≥250 | ≥240 | 185–250 | 200–305 | 205–350 | 240–355 |
| Elongation (%) | ≈20–23 | ≈20 | 28–30 | 28–30 | 25–30 | 24–29 |
| Where You can Use It | Plates, bars, beams | High-temp pipes | Deep drawing, forming | Car bodies, structural | Shafts, machinery parts | Bolts, rods |
Mechanical Properties
Knowing these properties helps you choose the right steel for your job. Here are some typical values for mild steel grades, with clear explanations of what each property means for you.
| ASTM A36 | ASTM A106 Grade B | AISI 1010 | AISI 1020 | ASTM A283 Grade C | EN 1.0038 (S235JR) | |
| Yield Strength: This tells you how much force you can put on the steel before it bends and won’t spring back. The higher the number, the stronger your steel will be when handling weight or pressure. | ~250 MPa (36 ksi) | ~240 MPa (35 ksi) | ~305 MPa (44 ksi) | 350 MPa (51 ksi) | ~205 MPa (30 ksi) | 235 MPa (34 ksi) |
| This shows how much you can pull or stretch the steel before it snaps. If your project needs to hold up under strong pulling or stretching, look for a higher number here. | 400–550 MPa (58–80 ksi) | ~415 MPa (60 ksi) | 365–505 MPa (53–73 ksi) | 420–550 MPa (61–80 ksi) | 380–515 MPa (55–75 ksi) | 360–510 MPa (52–74 ksi) |
| Elongation: This tells you how much the steel can stretch before it breaks. If you need your steel to bend or flex, a bigger percentage is better. | ~20% | ≥20% | ≥28% | ≥25% | ≥22% | 24% |
| Hardness (Brinell): This shows how well your steel resists scratches and dents. A higher number means your steel will stay smooth and look good longer. | 119–162 | 126 | 111–137 | 131–162 | 120–160 | 100–145 |
| Fatigue Strength: This tells you how well the steel holds up if you load and unload it over and over. If your parts move a lot, pick a steel with a higher fatigue strength. | ~190 MPa | ~145 MPa | N/A | N/A | N/A | N/A |
| Key Alloying Elements | C: 0.25%; Mn: 0.8–1.2% | C: 0.25%; Mn: 0.27–0.93% | C: 0.08–0.13%; Mn: 0.30–0.60% | C: 0.17–0.23%; Mn: 0.30–0.60% | C: 0.24%; Mn: 0.90% | C: 0.17%; Mn: 1.4% |
Keep in mind: The actual values can change a bit depending on the shape or thickness of your steel. Always double-check what you need for your own project.
This guide makes it easy to compare the grades, standards, chemistry, and properties of mild steel so you can choose the best material for your project.
Industry Specific Applications & Material Selection Guidance
Excessive Material Costs
How Low-Carbon Steels Help You Save Money
If you are worried about material costs for your project, low-carbon steels can help you save money. These steels are common, easy to find, and simple to use, which helps keep your costs low. Because they are easier to work with, you also spend less money on tools, labor, and fixing mistakes.
Good Choices for You:
- ASTM A36: Easy to weld and stays flat, so you don’t waste time or money fixing problems after welding.
- AISI 1010 / SAE 1010: Very low carbon, so less chance of cracks, which means fewer repairs for you.
- EN 1.0038 (S235JR): A popular choice in Europe, great when you want to keep things simple for big projects.
Why This Matters for You:
Low-carbon steels need less energy to process and are less likely to need repairs or to be thrown away. This means you spend less overall.
Manufacturing Difficulties
Make Your Work Easier with Low-Carbon Steels
Sometimes working with steel can be tough if it doesn’t cut, bend, or weld well. Low-carbon steels are known for being easy to handle. They won’t harden too much when you weld them, and they are simple to shape or machine. This makes your job quicker and easier.
Good Choices for You:
- AISI 1018: Great for when you need to machine parts to precise sizes.
- AISI 1008: Very soft and easy to shape, ideal for small or stamped parts.
- EN 1.0330 (DC01): Perfect for making thin, stamped parts if you’re working on European projects.
Why This Matters for You:
When you use low-carbon steel, you have fewer errors and your tools last longer. You spend less time fixing mistakes and get reliable parts faster.
Insufficient Structural Safety
Build Strong and Safe Structures
If you are making something that needs to be strong, especially in cold or tough conditions, low-carbon steels are a safe bet. They are tough and less likely to break or crack, keeping your projects safer.
Good Choices for You:
- ASTM A333 Grade 1: Good for pipes or projects in cold environments. These stay strong even when it’s freezing.
- ASTM A333 Grade 6: Used often for pipelines that carry cold liquids or gases.
- EN 1.0114 (S275JR): Works well for outdoor projects in Europe where the weather gets cold.
Why This Matters for You:
Low-carbon steels handle temperature changes well and won’t shatter or crack quickly. Your structures stay safe and last longer.
Fatigue Life and Reliability
Keep Your Projects Working Longer
Some parts in your projects may move, bend, or carry weight again and again. Low-carbon steels can bend without breaking, so they last longer when used for moving parts or frames.
Good Choices for You:
- AISI 1020 / SAE 1020: Good strength and flexibility for parts that move.
- EN 1.0038 (S235JR): Common in bridges or places that deal with repeated loads.
- ASTM A500 Grade B/C: Best for tubes or frame supports.
Why This Matters for You:
With these steels, your parts won’t crack after lots of use. They bend when needed but don’t break easily, so you can trust your project will work for a long time.
Conclusion
Mild steel is a strong, flexible and affordable material that can be used for many applications. Its unique combination of strength, ease of use and low cost gives your business a lot of benefits. Are you ready to find the best mild steel solution for you? Get in touch with HYT Metals today for expert help and a quote.