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A Comprehensive Guide to 1018 Steel
1018 steel, also known as AISI 1018 carbon steel—or simply SAE 1018—is a fundamental material with broad applications in various sectors because of its excellent mechanical properties and workability combination. This guide is aimed at offering a comprehensive overview of 1018 steel by considering its chemical composition, mechanical and physical properties, as well as the different applications where this alloy excels. Whether you are a materials engineer, a manufacturing professional, or simply someone curious about metal properties and uses, this guide will give you insights and practical knowledge that can be used. Let’s delve into the essential aspects of 1018 steel to establish why it is preferred for use in many industrial applications.
What is 1018 Steel?
1018 steel is a low-carbon alloy containing approximately 0.18% (by weight) of carbon. It is one of the most commonly available grades of carbon steel and is known for being highly weldable, machinable, and versatile. Due to its high carbon content, it exhibits good strength and ductility, making it widely used in machinery parts, automotive components, structural sections, and shafts. 1018 steel is often cold drawn or cold rolled to enhance its mechanical properties and surface texture. It is typically used in manufacturing and fabrication processes where a balance of strength, machinability, and affordability is desired.
Chemical Composition of 1018 Steel
1018 steel is a versatile, adaptable, medium-low carbon steel that exhibits excellent weldability, machinability, formability, and strength compared to lower carbon steel when in a normalized and hot forged state. It is popular among cold-rolled steels and is considered the top option for carburized gears, including pins, spindles, pinions, ratchets, and other machinery parts. Its main chemical components are as follows：
Table 1: Chemical Composition of 1018 Steel
| Element | Percentage（%） |
| Carbon (C) | 0.14 – 0.20 |
| Iron (Fe) | 98.81 – 99.26 |
| Manganese (Mn) | 0.60 – 0.90 |
| Phosphorus (P) | 0.0 – 0.04 |
| Sulfur (S) | 0.0 – 0.05 |
The Properties of 1018 Steel
The properties of common 1018 steel material are as follows:
Table 2: Physical Properties of 1018 Steel
| Properties | Metric | English |
| Density | 7.87 g/cc | 0.284 lb/in² |
| 1018 Steel Machinability | 0.78 | 0.78 |
| 1018 Steel Modulus of Elasticity | 205 GPa | 29700 ksi |
Table 3: Mechanical Properties of 1018 Steel
| Properties | Metric | English |
| 1018 Steel Ultimate Tensile Strength | 440 MPa | 63800 psi |
| 1018 Steel Tensile Yield Strength | 370 MPa | 53700 psi |
| Elongation at Break | 0.15 | 0.15 |
| Reduction of Area | 0.4 | 0.4 |
| 1018 Steel Hardness, Brinell | 126 | 126 |
| 1018 Steel Hardness, Knoop | 145 | 145 |
| 1018 Steel Hardness, Rockwell B | 71 | 71 |
| 1018 Steel Hardness, Vickers | 131 | 131 |
| 1018 Steel Modulus of Elasticity | 193 GPa | 28000 ksi |
| Bulk Modulus | 159 GPa | 23100 ksi |
| Shear Modulus | 77.2 GPa | 11200 ksi |
| Poissons Ratio | 0.29 | 0.29 |
Table 4: Thermal Properties of 1018 Steel
| Properties | Value | ||
| Electrical Resistivity | 0.0000159 ohm-cm | 0.0000159 ohm-cm | Temperature 0.000 °C/32.0°F, annealed condition |
| 0.0000219 ohm-cm | 0.0000219 ohm-cm | Temperature 100 °C/212°F, annealed condition | |
| 0.0000293 ohm-cm | 0.0000293 ohm-cm | Temperature 200 °C/392°F, annealed | |
| Specific Heat Capacity | 0.486 J/g-°C | 0.116 BTU/lb-°F | Temperature >=100°C/212°F, annealed |
| Thermal Conductivity | 51.9 W/m-K | 360 BTU-in/hr-ft²-°F | estimated based on similar materials |
Fabrication and Heat Treatment
Machinability
AISI 1018 carbon steel has a rating of 62% compared to AISI 1112 carbon steel. Machining produces a smooth finish with continuous and hard chips. This alloy can be machined under any conditions.
Forming
It is easy to shape AISI 1018 carbon steel in annealed conditions.
Welding
1018 steel can be welded using most conventional methods such as gas, resistance, oxyacetylene, and submerged arc welding.
Heat Treatment
AISI 1018 carbon steel can be hardened to 42 Rc in thin sections and 28-30 Rc in thicker sections over 4 inches.
Forging
The forging of AISI 1018 carbon steel can occur within the temperature range of 1825-2300°F.
Hot Working
AISI 1018 carbon steel is easily hot worked.
Cold Working
Cold working AISI 1018 carbon steel will impact its hardness and mechanical properties. Intermediate annealing is needed to counter the alloy’s tendency to work harden.
Annealing
This alloy can be completely annealed by soaking at 1650°F, followed by furnace cooling. Process annealing can be done at 1200°F.
Corrosion Resistance
SAE/AISI 1018 steel is an excellent option for applications requiring moderate corrosion resistance. As a low-carbon steel, it provides a balanced mix of strength and flexibility without the surface problems of higher-carbon steel. Its weldability adds versatility, making it suitable for various manufacturing processes.
AISI 1018 is also more cost-effective than higher-strength alloys, making it an appealing choice for projects with budget constraints. Although it provides decent corrosion resistance, it is best used in environments where severe corrosion is not a significant concern. Overall, the combination of corrosion resistance, weldability, and affordability makes SAE 1018 a practical choice for many engineering and manufacturing applications.
Equivalent Forms of 1018 Steel
The following are equivalent forms of 1018 steel:
Table 5: Equivalent-Grade Steels from Different Countries
| Country | Equivalent Steel Name |
| China | 15 # |
| European Union | C15E (1.1141) |
| Germany | 1.0401, C15, CK15 |
| France | XC15 |
| United Kingdom | 080M15 |
| Japan | S15C |
Common Forms of 1018 Steel
Typical forms of 1018 steel material include:
- 1018 Cold-Rolled Steel
1018 cold-rolled steel is processed at low temperatures, enhancing its surface finish and allowing the final product to meet tight tolerances. This type of steel exhibits excellent machinability and weldability, making it a popular choice for parts and components requiring smooth finishes. Its composition primarily consists of iron, manganese (about 0.60% to 0.90%), carbon (typically 0.18%), and minor traces of other elements; its microstructure generally consists of ferrite and pearlite. Because of its ease of machining and forming, 1018 cold-rolled steel is commonly used in shafts, pins, hinges, and other precision components.
- 1018 Steel Bar
The round, square, and hexagonal 1018 steel bar stock is versatile and can be machined into many different components. This variety has the same machinability and weldability qualities as other forms of 1018 steel. The shape of the stock is often a helpful starting point for manufacturers. Its primary ingredients are iron, carbon, manganese, and trace amounts of other alloying components. Its composition is the same as cold-rolled 1018 steel, with pearlite and ferrite making up its microstructure. Machinable and formable, 1018 steel bars produce bolts, studs, axles, and various machine components.
- 1018 Steel Sheet and Plate
The flat forms of 1018 steel sheets and plates make them ideal for shaping, welding, and general manufacturing. These sheets and plates are similar to other 1018 steel varieties, consisting primarily of iron and carbon (usually 0.18%) and manganese and minor alloying elements. They have outstanding workability and moderate strength. In their microstructure, pearlite and ferrite predominate. Common uses for 1018 steel sheets and plates include brackets, automotive panels, structural elements, and other applications requiring flat steel sections.
- 1018 Steel Wire
1018 steel wire is well-known for its weldability and versatility. Due to its ductility and formability, this type of steel is suitable for welding applications and construction projects. It primarily comprises iron and carbon, with minor alloying elements contributing to its properties. The microstructure of 1018 steel wire typically consists of ferrite and pearlite. This type of steel is widely used in welding processes, construction work, and for crafting wire-based products such as springs and fencing.
Processing Methods Suitable for 1018 Steel
The 1018 steel offers excellent machinability and decent strength, allowing for various processing methods. Operations such as turning, milling, drilling, and tapping can be carried out with minimal tool wear. Welding techniques like SMAW, GMAW, and GTAW are also applicable, although preheating and post-weld heat treatment may be necessary for optimal weld quality. Cold working processes like cold drawing and rolling allow for precise dimensioning and shaping of the steel’s mechanical properties in its final state. Heat treatment is not primarily for enhancing toughness, but annealing can be utilized to improve machinability and refine the microstructure. Furthermore, surface treatments such as carbonizing, nitriding, or blackening can significantly increase abrasion and corrosion resistance while enhancing aesthetics. The versatility of these processing methods makes 1018 steel a preferred choice for various applications in various industries.
Applications of 1018 Steel
1018 Steel has several applications, including:
Industrial Applications
Some of its applications in manufacturing involve:
- Automotive Industry: This material is used to produce crankshafts, pistons, gears, and transmission parts.
- Aerospace Industry: SS 1018 has an excellent strength-to-weight ratio and is utilized to produce fasteners and pins.
- Agricultural Industry: You can use 1018 steel to make tillers, plows, and cultivators.
- Oil and Gas Industry: Due to its ductility and elasticity, it can be used to manufacture fittings and valves in the oil and gas industry.
Commercial Applications
1018 steel has several commercial applications, including:
- Bicycle frames.
- Kitchen utensils and cutlery.
- Sports equipment like golf clubs.
- Typical hardware tools like wrenches and pliers.
Construction Applications
You can use 1018 steel in the construction industry. Common applications include:
- Structural support, like beams and columns.
- Reinforcing bars in concrete construction.
- Bolts, screws, and fasteners.
- Handrails and guardrails.
- Stair components.
- Metal letters
Maintenance of AISI 1018
You should regularly inspect your AISI 1018 components for wear, corrosion, and damage. Here’s how you can address common issues:
- Corrosion: AISI 1018 is prone to corrosion, so avoid storing it in salty or humid environments. Apply a protective coating, such as black oxide or oil, to shield it from corrosion.
- Wear: AISI 1018 may experience wear over time when exposed to abrasive materials. To prevent this, ensure that your AISI 1018 appliances are well-lubricated.
- Heat Damage: Components made of AISI 1018 steel are susceptible to heat damage under high temperatures. Utilizing annealing and quenching techniques can help prevent this issue.
Advantages & Disadvantages
Advantages:
SAE 1018 has several pros, such as:
- Weldability: SAE 1018 boasts excellent weldability, with TIG or MIG welding being suitable for its components.
- Machinability: SAE 1018 can be easily cut and shaped using various machines.
- Ductility: SAE 1018 steel can be formed into various shapes without cracking.
- Low Cost: SAE 1018 is an affordable option that can help reduce your production costs.
Disadvantages:
SAE 1018 has many limitations in addition to its benefits. These involve:
- Low Hardness: SAE 1018 is unsuitable for applications requiring a strong and tough material.
- Less Corrosion Resistance: SAE 1018 steel is prone to rusting, making it unsuitable for corrosive environments.
- Limited Wear Resistance: An SAE 1018 part may experience rapid wear and should not be used in highly abrasive environments.
Comparison Between 1018 Steel and Others
AISI 1018 is a type of low-carbon steel. There are many other types of carbon steels, like AISI 1020, 1045, and 4140. Let’s compare them:
AISI 1018 VS. AISI 1020
AISI 1020 has a higher carbon content than AISI 1018. Consequently, it is slightly more durable and harder, suitable for applications requiring strength and toughness. However, it is less machinable and formable than AISI 1018.
The variance in carbon content between the two grades is minimal; hence, they can be used almost interchangeably.
AISI 1018 VS. AISI 1045
AISI 1045 is another type of carbon steel with a higher carbon content, making it more durable and hard. However, compared to AISI 1018, it is less machineable and weldable. Due to its properties, AISI 1045 is commonly used in shafts and gears that require higher wear resistance.
AISI 1018 VS. AISI 1215
In carbon steels, 1215 Steel and 1018 Steel are distinct due to differences in composition and properties. 1215 Steel is known for its exceptional machinability, attributed to the addition of lead, but it tends to have inferior strength compared to 1018 Steel. On the other hand, 1018 Steel offers excellent machinability and higher strength, making it suitable for various applications, including general machining and the construction of structural components. Choosing between the two is up to specific needs, with 1215 Steel being preferred for high-volume precision parts, while 1018 Steel is more versatile for applications that need a balance of strength and machinability.
AISI 1018 VS. AISI 4140
AISI 4140 is a high-carbon, high-strength steel alloy with significantly higher carbon content. It also contains chromium and molybdenum, which make it extremely tough and suitable for the aerospace and oil and gas industries. However, it has considerably less ductility than AISI 1018.
Summary
SAE 1018 steel provides numerous benefits, making it an excellent material for various applications. Its strength and formability make it a top choice for automotive components, machinery, and everyday items. Additionally, its ease of machining adds to its appeal, making it practical for many projects.
This guide provides essential information about SAE/AISI 1018 steel and explains why it is a dependable and adaptable choice. Because of its wide range of applications and advantageous properties, AISI 1018 steel is a strong option for your next industrial project.
