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Carbon steel. Image Credit: Shutterstock.com/JE-MTY

1018 Steel: Uses, Composition, and Properties

Xomety X
By Team Xometry
November 9, 2023
 10 min read
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The metal known as AISI carbon steel 1018 — or simply 1018 steel — is a mainstay across various industries for its versatility. It is well known for its low price, easy machinability, and average strength. Predominantly made of iron and carbon, 1018 steel normally contains 0.18% carbon, which makes it easy to form and weld. It excels in cold forming and bending tasks, making it also ideal for bending and crimping processes. In cases of intense bending, stress relief may be required to avert cracks. Applications for this steel include: machine parts, bolts, and fasteners. It is well regarded for its balance of strength and workability.

This article will discuss 1018 steel, detailing its usage, composition, characteristics, and how it is manufactured. 

What Is 1018 Steel?

AISI 1018, most often called 1018 steel, stands out as a high-manganese carbon alloy celebrated for its exceptional machinability. Its acceptance of welds yields uniform, hard cases, making it a preferred choice for carburized parts. AISI 1018 offers a well-rounded blend of toughness, strength, and ductility, while its hot-rolled variant boasts improved machining and Brinell hardness. Strict manufacturing controls ensure top-tier quality, ideal for welding, forging, drilling, machining, cold drawing, and heat treating. The metal primarily consists of iron, manganese (0.60%-0.90%), and a small amount of carbon (0.14-0.20%).

What Is 1018 Steel Used For?

AISI 1018 is used for the following:

  1. Gears
  2. Axles
  3. Shafts
  4. Pistons
  5. Pins
  6. Fasteners
  7. Bolts
  8. Springs
  9. Sprockets

How Is 1018 Steel Made?

Most 1018 steel is created through a two-step procedure. First, primary steelmaking is performed on pig iron, which is iron that has been smelted from ore that has too much carbon. Molten pig iron is bubbled with oxygen, which oxidizes and eliminates excess carbon and impurities. The steel is next refined and alloyed during secondary steelmaking in a ladle. Components are added or subtracted to reach the appropriate alloy composition while maintaining perfect temperature control for chemical reactions. 

Is 1018 Steel Good for Knives?

No, 1018 steel is not suitable for knives. Its low carbon content results in poor cutting performance and edge retention, so the blades require frequent sharpening. While it can be fashioned into primitive iron knives, it doesn't compare to modern commercial knife steels. Many better options exist for knife-making. However, 1018’s price and availability make it useful as practice material for new metalsmiths. 

Is 1018 Steel Good for Forging?

Yes, 1018 steel is suitable for forging. It is a low-carbon steel that’s easy to weld and machine, making it a popular choice for blacksmithing and forging applications. Its relatively low carbon content makes it easier to shape and forge without the risk of cracking. However, as a mild steel, it may not be suitable for applications that require high strength or hardness.

What Is the Chemical Composition of 1018 Steel?

A typical chemical breakdown of 1018 steel is roughly as follows: iron (Fe) 98.81-99.26%, manganese (Mn) 0.60-0.90%, and carbon (C) 0.18%. Please note that while small amounts of additional elements might also be present, these are the primary constituents. For clarity, Table 1 shows the chemical makeup of 1018 steel:

Table 1: Chemical Composition of 1018 Steel
ChemicalPercentage
Chemical
Carbon (C)
Percentage
0.18 %
Chemical
Iron (Fe)
Percentage
98.81 – 99.26 %
Chemical
Sulfur (S)
Percentage
≤ 0.050 %
Chemical
Phosphorous (P)
Percentage
≤ 0.040 %
Chemical
Manganese (Mn)
Percentage
0.60 – 0.90 %

What Is the Carbon Content of 1018 Steel?

The carbon content of 1018 steel is 0.18%. This relatively low carbon percentage makes it a mild steel, suitable for applications where ease of forging, welding, and machining is more important than strength or hardness.

What Are the Properties of 1018 Steel?

Table 2 highlights the properties of 1018 steel:

Table 2: Properties of 1018 Steel
PropertyValue
Property
Density
Value
7.87 g/cm^3
Property
Yield Strength
Value
370 MPa
Property
Hardness
Value
Brinell - 126
Property
Magnetism
Value
Generally magnetic

What Is the Machinability Rating of 1018 Steel

When compared to a standardized reference material with a machinability grade of 100%, such as AISI 1112 steel, 1018 steel's machinability rating is about 70%. As a result, 1018 steel is slightly harder to machine than AISI 1112 steel, but it still has outstanding machinability properties, including: favorable chip formation, surface finish, and tool life during machining processes. It is therefore an effective choice for machining applications.

What Are the Characteristics of 1018 Steel?

Known for its adaptability and simplicity in fabrication, 1018 steel is a mild carbon steel. Its attributes include:

  1. Good Weldability: It’s suitable for welding processes, including MIG (metal inert gas) and TIG (tungsten inert gas).
  2. Excellent Machinability: 1018 forms clean cuts and smooth surfaces.
  3. Low Carbon Content: This makes it easy to forge without the risk of cracking.
  4. Moderate Strength: It is strong enough for many (but not all) applications.
  5. Ductility: This steel can be cold-worked or heat-treated.
  6. Cost-Efficiency: 1018 steel is budget-friendly, making it an attractive choice for cost-sensitive projects. 

Is 1018 Steel Mild Steel?

Yes, 1018 steel is considered mild steel. It is characterized by its low carbon content of roughly 0.18%. This low carbon level makes it easy to forge and weld, among other processes. To learn more, see our article on Mild Steel Composition.

Is 1018 Steel Hard or Soft?

Compared to alloy steels and steels with higher carbon content, 1018 steel is relatively ductile. Its mild character can be seen in its Brinell hardness rating of 126. The pliability of this metal makes it simple to machine, forge, and work with. That’s good for production, but it means 1018 steel is not the right choice if hardness or wear resistance are your top concerns. 

Is 1018 Steel Weldable?

Yes, 1018 steel is known for its good weldability. The low carbon content reduces the risk of cracking during welding. Common welding methods such as MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) suit 1018 steel well. Proper preheating and post-weld heat treatment may be necessary in certain cases to minimize the risk of distortion or cracking, but overall, 1018 steel is considered weldable.

Is 1018 Steel Magnetic?

Yes, 1018 steel is magnetic. Since its atomic structure is made up almost entirely of iron, which is inherently magnetic, this and most other carbon steels are magnetic as well. When exposed to a magnetic field, the iron atoms align in a way that attracts the metal to the magnetic field. 

What Are the Common Forms of 1018 Steel Material?

Common forms of 1018 steel material include:

1. 1018 Cold-Rolled Steel 

1018 cold-rolled steel is processed at low temperatures. The method enhances its surface finish and allows the final product to meet tight tolerances. This form of steel exhibits excellent machinability and weldability, making it a popular choice for parts and components with smooth finishes. With a composition primarily consisting of iron, carbon (typically 0.18%), manganese (about 0.60% to 0.90%), and minor traces of other elements, its microstructure typically consists of ferrite and pearlite. Because it’s simple to machine and form, 1018 cold-rolled steel is often used in shafts, pins, hinges, and other precision components.

2. 1018 Steel Bar

Round, square, and hexagonal 1018 steel bar stock is a versatile material that may be machined into many different types of components. This variety exhibits the same machinability and weldability qualities as other forms of 1018 steel, and the shape of the stock is often a useful starting point for manufacturers. Its major ingredients are iron, carbon, manganese, and trace amounts of other alloying components. Its composition is the same as cold-rolled 1018 steel: pearlite and ferrite make up its microstructure. Machinable and formable, 1018 steel bars are used in the production of bolts, studs, axles, and numerous machine components.

3. 1018 Steel Sheet and Plate

The flat forms of 1018 steel sheets and plates make them ideal for forming, welding, and general manufacturing. These sheets and plates have a similar composition to other 1018 steel varieties, consisting mostly of iron and carbon (usually 0.18%), as well as manganese and minor alloying elements. They have excellent workability and moderate strength. In their microstructure, pearlite and ferrite predominate. Automotive panels, brackets, structural elements, and other applications requiring flat steel sections are common uses for 1018 steel sheets and plates.

4. 1018 Steel Wire

1018 steel wire is renowned for its weldability and versatility. Because it’s so ductile and formable, this form of steel is well-suited for welding applications and construction projects. Its composition primarily consists of iron and carbon, with minor alloying elements contributing to its properties. The microstructure of 1018 steel wire typically features ferrite and pearlite. This form of steel is widely used in welding processes, construction work, and for crafting wire-based products such as springs and fencing.

What Are the Equivalents of 1018 Steel?

Table 3 highlights the equivalents of 1018 steel in different countries:

Table 3: Equivalents of 1018 Steel
CountryEquivalent Steel Name
Country
China
Equivalent Steel Name
15 #
Country
European Union
Equivalent Steel Name
C15E (1.1141)
Country
Germany
Equivalent Steel Name
1.0401, C15, CK15
Country
France
Equivalent Steel Name
XC15
Country
United Kingdom
Equivalent Steel Name
080M15
Country
Japan
Equivalent Steel Name
S15C

What Are the Advantages of Using 1018 Steel?

Advantages of using AISI 1018 mild/low-carbon steel include:

  1. It can be easily welded using various methods, making it suitable for a wide range of fabrication processes.
  2. When carburized, it produces a uniformly harder surface layer, enhancing wear resistance in applications like gears and shafts.
  3. 1018 is considered one of the best choices for carburized parts due to its response to case hardening, making it suitable for applications that need better surface hardness. 
  4. It offers a good balance of toughness, strength, and ductility, making it versatile for various engineering and structural applications.

What Are the Disadvantages of Using 1018 Steel?

Disadvantages of using 1018 steel include:

  1. It has a relatively low tensile and yield strength compared to other steel grades like 4140 steel.
  2. It may only be suitable for high-wear applications with additional treatment.
  3. The metal is prone to corrosion due to its low alloy content compared to 4140 steel.
  4. It may exhibit limited wear resistance in demanding applications.

Is 1018 Steel Expensive?

No, 1018 steel is not expensive. It is considered a low-cost option among steel grades due to its simple composition and widespread availability, making it one of the most economical options on the market. 

How Does 1018 Steel Differ From Ordinary Steel?

AISI 1018 steel is a very common type of steel. It stands out for having a low carbon content and being machinable and weldable. Its versatility means it sees use across most industries. To learn more, see our article on What Makes Up Steel.

Is 1018 Steel a Stainless Steel?

No, 1018 steel is not a type of stainless steel. It lacks the chromium content that gives stainless steel its resistance to rust. 1018 steel is a low-carbon, mild steel.

Is 1018 Steel Stronger Than 1045 Steel?

No, 1018 steel is not stronger than 1045 steel. 1045 steel has a higher carbon content, which gives it greater tensile and yield strength compared to the lower carbon content of 1018 steel.

Is 1018 Steel Better Than Other Medium-Carbon Steel?

It depends on the specific application. 1018 steel offers good machinability and weldability but may not be better than other medium-carbon steels in terms of strength or hardness.

What Is the Difference Between 1018 Steel and A36 Steel?

The production processes and carbon content of 1018 steel and A36 steel are the two key distinctions between them. While A36 is hot-rolled and contains 0.25-0.29% carbon, 1018 is cold-rolled with 0.18% carbon.

Summary

This article presented 1018 steel, explained it, and discussed its various uses and composition. To learn more about 1018 steel, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

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Xomety X
Team Xometry
This article was written by various Xometry contributors. Xometry is a leading resource on manufacturing with CNC machining, sheet metal fabrication, 3D printing, injection molding, urethane casting, and more.