All About Mild Steel
Learn more about mild steel and how it's used in manufacturing.
Mild steel, also known as low-carbon steel, is one of the most widely used steels. It is used in the construction and automotive industries, and for fencing, signs, and other applications. Generally speaking, it has good weldability, machinability, and ductility. Mild steel is primarily characterized by having a carbon content of less than 0.2 % by weight. The 4-digit AISI (American Iron and Steel Institute) classification codes for mild steel start with "10" and end with two digits that are less than 20, indicating the approximate carbon content of the steel in hundredths.
This article will explore the chemical composition, mechanical properties, grades, and characteristics of mild steel.
What is Mild Steel?
Mild steel is an iron alloy with carbon as its main alloying element. It is one of the most widely used forms of steel and can be applied to a range of general-purpose applications. Mild steel owes its popularity to its adequate strength at low cost, in addition to its excellent machinability and weldability. Various grades of mild steel have differing amounts of carbon with higher carbon contents wrestling in increased strength at the expense of ductility. In some cases, additional alloying elements are added to improve properties such as tensile strength, corrosion resistance, and wear resistance.
Mild steel is made up of an iron (Fe) base with the addition of small amounts of carbon. Low-carbon steel is typically defined as having less than 0.2 % carbon by ASM International. Different grades of mild steel are defined by their differing levels of carbon. Another common alloying element is manganese (Mn).
Grades of Mild Steel
There are many different grades of mild steel that you could use. Mild steels classified according to the AISI (American Iron and Steel Institute) numbering system will all begin with “10” as their first two digits signifying their low carbon content. Low-carbon steel, and by extension mild steel, will have the final 2 digits of the designation as any number less than 20 (approximate carbon content multiplied by 100). Most mild steel has low (<1%) quantities of phosphorus and sulfur and these elements are actively limited as they are considered impurities. Some common grades are listed in Table 1 below:
| Classification | Approximate Equivalents | Key Points |
|---|---|---|
Classification AISI 1008 | Approximate Equivalents DIN 1.0204 | Key Points Excellent cold formability |
Classification AISI 1010 | Approximate Equivalents DIN 1.0301 | Key Points Low strength, used for magnet cores |
Classification AISI 1015 | Approximate Equivalents DIN 1.0401 | Key Points Wear-resistant, good machinability |
Classification AISI 1018 | Approximate Equivalents DIN 1.0419 | Key Points Excellent for carburizing applications, good machinability |
Classification AISI 1020 | Approximate Equivalents DIN 1.0044 | Key Points A good balance of strength and ductility, |
| Type of Mild Steel | Modulus of Elasticity (GPa) | Brinell Hardness | Ultimate Tensile Strength (MPa) | Yield Strength (MPa) | Elongation at Break (%) | Steel Density kg/m3 |
|---|---|---|---|---|---|---|
Type of Mild Steel AISI 1008 | Modulus of Elasticity (GPa) 200 | Brinell Hardness 95 | Ultimate Tensile Strength (MPa) 340 | Yield Strength (MPa) 285 | Elongation at Break (%) 20 | Steel Density kg/m3 7.87 |
Type of Mild Steel AISI 1010 | Modulus of Elasticity (GPa) 205 | Brinell Hardness 105 | Ultimate Tensile Strength (MPa) 365 | Yield Strength (MPa) 305 | Elongation at Break (%) 20 | Steel Density kg/m3 7.87 |
Type of Mild Steel AISI 1015 | Modulus of Elasticity (GPa) 205 | Brinell Hardness 111 | Ultimate Tensile Strength (MPa) 385 | Yield Strength (MPa) 325 | Elongation at Break (%) 18 | Steel Density kg/m3 7.87 |
Type of Mild Steel AISI 1018 | Modulus of Elasticity (GPa) 205 | Brinell Hardness 126 | Ultimate Tensile Strength (MPa) 440 | Yield Strength (MPa) 370 | Elongation at Break (%) 15 | Steel Density kg/m3 7.87 |
Type of Mild Steel AISI 1020 | Modulus of Elasticity (GPa) 186 | Brinell Hardness 121 | Ultimate Tensile Strength (MPa) 420 | Yield Strength (MPa) 350 | Elongation at Break (%) 15 | Steel Density kg/m3 7.87 |
Type of Mild Steel S275 J0 | Modulus of Elasticity (GPa) 205 | Brinell Hardness 121 | Ultimate Tensile Strength (MPa) 430 - 580 | Yield Strength (MPa) 275 | Elongation at Break (%) 21 | Steel Density kg/m3 7.85 |
Type of Mild Steel S355 J0 | Modulus of Elasticity (GPa) 210 | Brinell Hardness 146 | Ultimate Tensile Strength (MPa) 510 - 680 | Yield Strength (MPa) 355 | Elongation at Break (%) 20 | Steel Density kg/m3 7.80 |
Table Credit: matweb.com
| Classification | Carbon Content (% Weight) | Secondary Alloying Elements (% Weight) |
|---|---|---|
Classification AISI 1008 | Carbon Content (% Weight) <0.1 | Secondary Alloying Elements (% Weight) 0.3 to 0.5 Mn; 0.04 P; 0.05 S |
Classification AISI 1010 | Carbon Content (% Weight) 0.08 to 0.13 | Secondary Alloying Elements (% Weight) 0.3 to 0.6 Mn; 0.04 P; 0.05 S |
Classification AISI 1015 | Carbon Content (% Weight) 0.13 to 0.18 | Secondary Alloying Elements (% Weight) 0.3 to 0.6 Mn; 0.04 P; 0.05 S |
Classification AISI 1018 | Carbon Content (% Weight) 0.14 to 0.2 | Secondary Alloying Elements (% Weight) 0.6 to 0.9 Mn; 0.04 P; 0.05 S |
Classification AISI 1020 | Carbon Content (% Weight) 0.17 to 0.23 | Secondary Alloying Elements (% Weight) 0.3 to 0.6 Mn; 0.04 P; 0.05 S |
Classification S275 | Carbon Content (% Weight) 0.18 | Secondary Alloying Elements (% Weight) 1.5 Mn; 0.030 P; 0.030 S; 0.012 N; 0.55 Cu |
Classification S355 | Carbon Content (% Weight) 0.2 | Secondary Alloying Elements (% Weight) 1.6 Mn; 0.030 P; 0.030 S; 0.012 N; 0.55 Cu |
Table 3: matweb.com
Summary
To learn more about mild steel and all the ways that you can use it in manfacturing, contact a Xometry representative.
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