1018 Steel: Uses, Composition, and Properties
High workability, medium strength, and low price — a winning combo
Known in industry for its adaptability and machinability, 1018 is a low-carbon, mild steel used to make many different parts with clean cuts and smooth surfaces. These include structural and precision parts, fasteners, pistons, sprockets, gears, shafts, pins, hinges, bolts, studs, axles, and vehicle panels, among many others. In this guide, we’ll detail all the important need-to-know details about this useful steel, including its composition, properties, and forms.
What is 1018 Steel?
As the most common (or at least one of them) cold-rolled steels in the world, 1018 is classed as a free-machining steel grade, meaning that small chips form when it’s machined. This is a good thing as it makes it easier to work with and manipulate into whatever shape you need. That, and its great tool life, is why it’s so often chosen by those in machining. Like all the other steels in its category, 1018 is mostly made up of iron, with manganese as its main alloying element, followed by carbon and trace amounts of sulfur and phosphorus. It’s the carbon in its makeup that makes 1018 so easy to form with cold forming, bending, and crimping.
It can be welded with the MIG (metal inert gas) and TIG (tungsten inert gas) processes, but will need preheating and heat treatment after welding to reduce the likelihood of cracks or distortion. In machining, 1018 is chosen for its good chip formation and tool life. It’s a staple for engineering and structural uses due to how easy it is to fabricate with a bunch of methods and finishing work, and its simple composition, which keeps its cost on the low side. It’s also easy to get—it’s widely available and you’re not likely to be put on a waiting list for it.
What Is 1018 Steel Used For?
AISI 1018 is used for the following:
- Gears
- Axles
- Shafts
- Pistons
- Pins
- Fasteners
- Bolts
- Springs
- Sprockets
How Is 1018 Steel Made?
To make 1018, there are typically two steelmaking steps, as follows:
Primary: The first step is removing the excess carbon and any impurities from pig iron by blowing air through the melt so that it oxidizes.
Secondary: The molten metal is then transferred to a large container called a ladle (no, not the soup kind—this one is shaped like a bucket and has a 44-pound weight capacity—but it does have a handy spout), and the alloy metals are added to it. All this happens at highly controlled temperatures to make sure all the right chemical reactions are obtained for the final metal to have the necessary properties.
This steel comes in many forms, and you’ll choose the best one for the job, according to what you need to make. In addition to cold-rolled, it comes in round, square, or hexagon-shaped bars, sheets, and plates, and wire.
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?
Here’s what is in 1018 carbon steel:
| Chemical | Percentage |
|---|---|
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 % |
Chemical Composition of 1018 Steel
Let’s break down what qualities these elements give to 1018. At a microscopic level, 1018’s internal structure is a mix of pearlite (the hard and strong part) and ferrite (the softer, more bendable part). As with most other carbon steels, the iron makes this metal magnetic. The low amount of carbon makes it ductile, easy to forge with a variety of methods (i.e., blacksmithing), and less prone to cracking during welding (but as mentioned earlier, you’ll have to do some post-welding work).
In general, it won’t be the best option for super strong, very hard, or wear-resistant parts, but you could treat it to make it more appropriate for high-wear applications. While this is the steel to choose for making carburized parts (it responds impeccably to case hardening and forms a harder surface layer), you wouldn’t want to make knives from it.
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?
The below table lists 1018’s physical properties.
| Property | Value |
|---|---|
Property Density | Value 7.87 g/cm^3 |
Property Yield Strength | Value 370 MPa |
Property Hardness | Value Brinell - 126 |
Property Magnetism | Value Generally magnetic |
Properties of 1018 Steel
As you can see, it’s not the strongest or hardest in its category, but it’s as tough as it can be in order to remain malleable for fabrication. When hot-rolled, its machinability and hardness levels are increased. It could also be susceptible to wear (without treatment) and corrosion, as it has a lower alloy content than some of its counterparts.
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.
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.
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 Characteristics of 1018 Steel?
Known for its adaptability and simplicity in fabrication, 1018 steel is a mild carbon steel. Its attributes include:
- Good Weldability: It’s suitable for welding processes, including MIG (metal inert gas) and TIG (tungsten inert gas).
- Excellent Machinability: 1018 forms clean cuts and smooth surfaces.
- Low Carbon Content: This makes it easy to forge without the risk of cracking.
- Moderate Strength: It is strong enough for many (but not all) applications.
- Ductility: This steel can be cold-worked or heat-treated.
- Cost-Efficiency: 1018 steel is budget-friendly, making it an attractive choice for cost-sensitive projects.
Heat Treating 1018 Steel
We’ve listed out the different temperatures that 1018 steel needs to reach for certain processes in the table below.
| Process | Temperature |
|---|---|
Process Annealing | Temperature 1,550–1,620°F |
Process Carburizing | Temperature 1,650–1,700°F |
Process Case hardening | Temperature 1,500–1,600°F |
Process Core refinement | Temperature 1,450–1,500°F |
Process Forging | Temperature 2,100–2,250°F |
Process Normalizing | Temperature 1,650–1,700°F |
Process Stress relief | Temperature 1,000–1,200°F |
1018 Steel Temperature Guide
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?
While this steel is known as 1018 in the USA, it’s referred to differently in other countries. Below you’ll find its equivalent international names.
| Country | Equivalent 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 |
Equivalents of 1018 Steel
What Are the Advantages of Using 1018 Steel?
Advantages of using AISI 1018 mild/low-carbon steel include:
- It can be easily welded using various methods, making it suitable for a wide range of fabrication processes.
- When carburized, it produces a uniformly harder surface layer, enhancing wear resistance in applications like gears and shafts.
- 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.
- 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:
- It has a relatively low tensile and yield strength compared to other steel grades like 4140 steel.
- It may only be suitable for high-wear applications with additional treatment.
- The metal is prone to corrosion due to its low alloy content compared to 4140 steel.
- 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.
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.
How Xometry Can Help
If you’re after a highly formable carbon steel, 1018 might be just what you need. If strength or hardness are at the top of your priority list (perhaps you need to make parts that are more resistant to wear and the elements), you might want to look into a medium-carbon steel instead. Reach out to one of our reps for more information and/or guidance in the right direction, or upload your designs to our Instant Quoting Engine for a free quote and no-obligation quote.
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