Author: Scott Bredemann
Updated: 05/13/2025 | Read Time: 7mins
Mild steel is one of the most commonly used materials in manufacturing and construction. Known for its low carbon content, it brings a balance between strength, ductility, and ease of fabrication. You’ll find it in everything from structural beams to brackets on your garage shelves. This article breaks down what mild steel is, its key properties, common uses, and how it compares to other types of steel.
What is Mild Steel?
Mild steel, also known as low-carbon steel, is a type of carbon steel that contains a relatively small amount of carbon—usually around 0.05% to 0.25%. Because of this low carbon content, it’s softer and more ductile than higher-carbon steels, making it easier to shape, weld, and machine. You might also hear it referred to simply as plain steel, soft steel, or even cold-rolled steel, depending on how it’s processed.
Unlike stainless steel, mild steel doesn’t have added chromium or nickel, which means it’s not naturally corrosion-resistant. But that tradeoff comes with some advantages—it’s less expensive, widely available, and extremely versatile. It’s the kind of material you’ll find in everything from car frames and pipelines to fences and furniture, and it’s often the go-to choice for general-purpose metalworking.
Mechanical Properties of Mild Steel vs Other Metals
| Property | Mild Steel | Stainless Steel (304) | Carbon Steel (1045) | Aluminum (6061) | Titanium (Grade 5) | Copper |
|---|---|---|---|---|---|---|
| Density (g/cm³) | 7.85 | 8.0 | 7.87 | 2.7 | 4.43 | 8.96 |
| Tensile Strength (MPa) | 350-550 | 515-620 | 570-700 | 310 | 900-1200 | 220-400 |
| Yield Strength (MPa) | 200-350 | 205-310 | 320-490 | 270 | 830-1100 | 70-365 |
| Young’s Modulus (GPa) | 200 | 193-200 | 200-205 | 68-70 | 110-114 | 110-130 |
| Hardness (Brinell) | 120-180 | 170-220 | 170-210 | 95-105 | 330-375 | 35-120 |
| Elongation at Break (%) | 15-30 | 30-40 | 12-20 | 12-17 | 10-15 | 10-45 |
| Thermal Conductivity (W/m·K) | 45-55 | 16-18 | 49-54 | 167-180 | 6.7-7.2 | 385-400 |
| Electrical Conductivity (% IACS) | 3-15 | 2-3 | 5-15 | 30-45 | 0.8-1.5 | 100 |
| Melting Point (°C) | 1450-1530 | 1400-1450 | 1432-1495 | 580-650 | 1605-1660 | 1083 |
| Corrosion Resistance | Poor | Excellent | Poor | Good | Excellent | Good |
| Magnetic | Yes | No (304) | Yes | No | No | No |
| Relative Cost | Low | Medium-High | Low-Medium | Medium | Very High | Medium-High |
| Strength-to-Weight Ratio | Medium | Medium | Medium-High | High | Very High | Low-Medium |
| Machinability | Good | Fair | Good | Excellent | Poor | Excellent |
| Weldability | Excellent | Good | Good | Good | Fair | Excellent |
Physical Properteries of Mild Steel
| Property | Mild Steel | Stainless Steel (304) | Carbon Steel (1045) | Aluminum (6061) | Titanium (Ti-6Al-4V) | Copper |
|---|---|---|---|---|---|---|
| Specific Heat Capacity | 0.46-0.50 | 0.50 | 0.47-0.49 | 0.89-0.96 | 0.52-0.56 | 0.38-0.40 |
| Thermal Expansion Coefficient | 11.7-13.0 | 17.3 | 11.5-12.8 | 23.6 | 8.6-9.0 | 16.5-17.5 |
| Electrical Resistivity | 0.14-0.18 | 0.72-0.78 | 0.15-0.19 | 0.038-0.042 | 1.68-1.78 | 0.017-0.019 |
| Electrical Conductivity | 5.5-7.1 | 1.3-1.4 | 5.2-6.7 | 23.8-26.3 | 0.56-0.60 | 52.6-58.8 |
| Magnetic Permeability | 100-2000 | 1.0-1.02 | 100-2000 | 1.0 | 1.0 | 0.999 |
| Curie Temperature | 770 | – | 770 | – | – | – |
| Reflectivity | 0.55-0.60 | 0.60-0.65 | 0.50-0.55 | 0.70-0.75 | 0.55-0.60 | 0.75-0.85 |
| Emissivity | 0.07-0.10 | 0.10-0.16 | 0.07-0.10 | 0.02-0.06 | 0.10-0.19 | 0.02-0.05 |
| Oxidation Resistance | Poor | Excellent | Poor | Good | Excellent | Good |
| Corrosion Rate (mm/year) | 0.1-0.2 | 0.001-0.01 | 0.1-0.3 | 0.01-0.05 | 0.001-0.005 | 0.01-0.1 |
| Surface Roughness (µm Ra) | 1.6-6.3 | 1.0-3.2 | 1.6-6.3 | 0.8-3.2 | 1.0-3.2 | 0.4-1.6 |
| Recrystallization Temperature (°C) | 450-700 | 650-850 | 450-700 | 250-350 | 700-850 | 150-300 |
| Sound Velocity (m/s) | 5900-6000 | 5800-5900 | 5850-5950 | 6300-6400 | 4900-5100 | 4600-4700 |
| Damping Capacity | Low | Low | Low | Low | Medium | Low |
| Carbon Content (% by weight) | 0.05-0.25 | ≤0.08 | 0.43-0.50 | – | ≤0.08 | – |
| Density (g/cm³) | 7.85 | 8.0 | 7.87 | 2.7 | 4.43 | 8.96 |
| Thermal Conductivity (W/m·K) | 45-55 | 16-18 | 49-54 | 167-180 | 6.7-7.2 | 385-400 |
| Melting Point (°C) | 1450-1530 | 1400-1450 | 1432-1495 | 580-650 | 1605-1660 | 1083 |
Machinablility and Weldability of Mild Steel
Mild steel is one of the easiest metals to machine and weld, which is a big reason it’s used so often in workshops and factories. It doesn’t gum up tools, and it handles drilling, cutting, and grinding without much trouble. When it comes to welding, mild steel takes to just about any method—MIG, TIG, stick—you name it. It also doesn’t require special prep or exotic filler materials, which keeps things simple on the shop floor.
Another bonus is that mild steel is forgiving. If you’re a beginner working on a project or troubleshooting a repair, it’s a material that lets you make adjustments without cracking or becoming brittle. That flexibility makes it a favorite not just in industry, but also in hobby welding and prototyping.
Common Grades of Mild Steel
| Grade | Carbon Content (%) | Key Properties | Common Applications |
|---|---|---|---|
| AISI 1008 | 0.10 max |
– Excellent formability – Good surface finish – High ductility – Good weldability |
– Cold-rolled sheet metal – Stampings and formed parts – Wire products – Automotive body panels |
| AISI 1010 | 0.08-0.13 |
– Good weldability – Good formability – Moderate strength – Excellent extruding characteristics |
– General structural components – Automotive bodies – Pipes and tubes – Rivets and bolts |
| AISI 1015 | 0.13-0.18 |
– Predictable qualities – Excellent welding properties – Good bending characteristics – Higher strength than 1010 |
– Structural applications – Formed parts requiring higher strength – Chain links – Machinery parts |
| AISI 1018 | 0.15-0.20 |
– Balanced strength and ductility – Good machinability – Excellent weldability – Better surface finish than hot-rolled grades |
– Shafts and pins – General-purpose machinery parts – Structural components – Precision parts |
| AISI 1020 | 0.18-0.23 |
– Higher strength than 1018 – Good machinability – Good formability – Carburizes well |
– Automotive camshafts – Gears and shafts – Machine parts – Hydraulic couplings |
| ASTM A36 | 0.25-0.29 |
– High strength – Excellent weldability – Good ductility – Lower cost than cold-rolled grades |
– Structural beams and columns – Bridges and buildings – Steel frames – Heavy equipment |
| AISI 1025 | 0.22-0.28 |
– Higher carbon content for greater strength – Good weldability – Retains form after machining – Reasonable ductility |
– Machinery parts – Structural applications – Axles and shafts – Forged components |
| AISI 1045 | 0.43-0.50 |
– Medium carbon steel – Higher strength and hardness – Good wear resistance – Heat treatable |
– Bolts and studs – Shaft parts – Hydraulic components – Machine parts requiring higher strength |
| AISI 1117 | 0.14-0.20 |
– Low carbon, high manganese – Good machinability – Deep and uniform case hardening – Good for bending |
– Parts requiring case hardening – Gears and pinions – Fasteners – Automotive components |
Parting Thoughts
At MISUMI USA, we offer a comprehensive selection of mild steel products and components, including configurable and custom parts, designed to meet your specific manufacturing needs. Our easy-to-use online tools allow you to quickly configure parts to your exact specifications, ensuring optimal performance and efficiency in every project. Explore our extensive range of steel products, including 18/10 steel, and 4140 steel products today and discover how MISUMI USA can support your manufacturing efforts with high-quality, customizable solutions.