SAE 1018 Steel – Chemical Composition, Equivalent Material, Properties and Uses

by AMC

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Posted on December 02, 2023 at 12:57 PM

SAE 1018 mild/low carbon steel is renowned for its exceptional weldability, contributing to ease in fabrication. This steel exhibits the capability to produce a uniform and harder case, making it particularly well-regarded for carburized parts. The balanced combination of toughness, strength, and ductility positions AISI 1018 as a preferred choice in various applications. In its hot-rolled form, AISI 1018 showcases significant mechanical properties, enhancing its suitability for a wide range of uses. The improved machining characteristics of SAE 1018 further contribute to its versatility, making it favorable for applications that demand precision and intricate machining. Additionally, this steel boasts a high Brinell hardness measure, underscoring its durability and suitability for applications where hardness is a critical factor. Overall, AISI 1018 stands out as a reliable and versatile mild/low carbon steel, offering a well-rounded combination of properties for diverse industrial applications.

SAE 1018 Chemical Composition

Element	Content
Carbon, C	0.14 – 0.20 %
Iron, Fe	98.81 – 99.26 % (as remainder)
Manganese, Mn	0.60 – 0.90 %
Phosphorous, P	≤ 0.040 %
Sulfur, S	≤ 0.050 %

SAE 1018 Chemical Properties

SAE 1018 is a low-carbon steel containing approximately 0.6% to 0.9% manganese and trace amounts of other elements. This composition renders it well-suited for numerous automotive and machinery applications. When utilized in the cold-drawn or "turned and polished" condition, AISI 1018 exhibits enhanced yield and tensile strength, along with improved machinability in comparison to its hot-rolled or regular AISI 1010 counterpart.

The steel's chemical makeup imparts excellent weldability, facilitating easy connection through various robust joints and welding techniques. Its versatility extends its presence into diverse industrial applications, ranging from construction vehicles to smaller components like screws and nuts. SAE / AISI 1018, with its balanced chemical properties, stands as a reliable choice in the fabrication of tools and equipment, contributing to the robustness and functionality of a wide array of industrial applications.

SAE 1018 Mechanical Properties

The mechanical properties of SAE/AISI 1018 steel encompass key characteristics:

• Tensile Strength: The ultimate strength falls within the range of 380 MPa to 540 MPa.
• Yield Strength: The maximum strength ranges from 310 MPa to 420 MPa.
• Elongation at Break: Typically, the elongation at break falls within the range of 21-23%.

It's noteworthy that the hardness of SAE/AISI 1018 steel is influenced by the heat treatment process employed during manufacturing. The application of specific heat treatment methods can either increase or decrease the hardness, providing flexibility in tailoring the material's properties to meet specific requirements. These mechanical properties collectively contribute to the suitability and versatility of AISI 1018 steel in various industrial applications.

Mechanical Properties	Metric	Imperial
Hardness, Brinell	126	126
Hardness, Knoop (Converted from Brinell hardness)	145	145
Hardness, Rockwell B (Converted from Brinell hardness)	71	71
Hardness, Vickers (Converted from Brinell hardness)	131	131
Tensile Strength, Ultimate	440 MPa	63800 psi
Tensile Strength, Yield	370 MPa	53700 psi
Elongation at Break (In 50 mm)	15.0 %	15.0 %
Reduction of Area	40.0 %	40.0 %
Modulus of Elasticity (Typical for steel)	205 GPa	29700 ksi
Bulk Modulus (Typical for steel)	140 GPa	20300 ksi
Poissons Ratio (Typical For Steel)	0.290	0.290
Machinability (Based on AISI 1212 steel. as 100% machinability)	70 %	70 %
Shear Modulus (Typical for steel)	80.0 GPa	11600 ksi

SAE/ AISI 1018 Physical Properties

SAE/AISI 1018 stands out as a highly versatile low-carbon steel with exceptional physical properties, contributing to its widespread use across various industries:

• Machinability: AISI 1018 boasts excellent machinability properties, facilitating easy fabrication and forming processes.
• Cold-Forming: The steel can be cold-formed with ease, providing flexibility in manufacturing and shaping.
• Durability and Weldability: AISI 1018 exhibits exceptional durability and weldability, making it suitable for a broad range of applications.
• Yield Strength: With a yield strength of 393 MPa, AISI 1018 offers good mechanical strength, ensuring reliability in structural applications.
• Ductility: The steel maintains favorable ductility levels, enhancing its ability to withstand deformation without fracture.
• Wear Resistance: Impressive wear resistance adds to the durability of AISI 1018, making it suitable for applications subjected to abrasion.
• Thermal Conductivity: High thermal conductivity of AISI 1018 facilitates efficient heat-treating processes, contributing to its versatility.
• Low Thermal Expansion Rate: The low thermal expansion rate further enhances the material's suitability for various temperature conditions.

Overall, the outstanding physical properties of SAE/AISI 1018, including its machinability, durability, and thermal characteristics, make it a preferred choice for designers seeking reliable and efficient metal components in diverse applications.

Physical Properties	Metric	Imperial
Density	7.87 g/cc	0.284 lb/in3

SAE 1018 Equivalent Material

AMS 5069	ASTM A29	ASTM A512	ASTM A611 (D-1)	ASTM A635
AMS 5069A	ASTM A510	ASTM A794	ASTM A519	ASTM A544
ASTM A108	ASTM A513	ASTM A830	ASTM A545	ASTM A548
ASTM A549	ASTM A659	SAE J412	SAE J1397	MIL S-11310 (CS 1018)
ASTM A576	SAE J403	SAE J414	MIL J-1397	MIL J-403
MIL J-412

SAE 1018 Steel Corrosion Resistance:

SAE/AISI 1018 steel emerges as a commendable choice for applications where moderate corrosion resistance is a requirement. This low alloy steel strikes a favorable balance between strength and flexibility, avoiding surface or hardness distortions often associated with higher carbon steels. The weldability of SAE/AISI 1018 further enhances its versatility, allowing for seamless integration into various manufacturing processes.

Notably, SAE/AISI 1018 presents an advantageous cost factor compared to other higher-strength alloys, making it an attractive option for those working within budget constraints. This alloy, combining excellent corrosion resistance with added strength, becomes a prudent choice for applications that aren't highly susceptible to corrosive elements in their environment. The overall package of corrosion resistance, weldability, and cost-effectiveness positions SAE/AISI 1018 as a wise and practical option for a range of engineering and manufacturing needs.

AISI 1018 Applications:

SAE/AISI 1018 finds widespread use across diverse industries due to its versatile properties. Some common applications include:

• Automotive Components: Widely employed in gears, axles, shafts, pistons, pins, fasteners, bolts, springs, sprockets, and crankshafts for automotive engines. Its high tensile strength and good formability make it a preferred choice.
• Furniture Manufacturing: Used in furniture frames and components owing to its excellent machinability properties. Its ease of shaping allows for the creation of desired forms in furniture construction.
• Food Production Equipment: Due to its corrosion resistance qualities, AISI 1018 is utilized in food production equipment. It is considered a safe material for machinery parts that come into contact with food items or liquids during the production process.

These applications showcase the adaptability of AISI 1018 across different industries, emphasizing its role in automotive engineering, furniture manufacturing, and food processing. The combination of strength, formability, machinability, and corrosion resistance positions SAE/AISI 1018 as a reliable and versatile material for a broad spectrum of engineering and manufacturing needs.

Heat Treatment of SAE/AISI 1018 Steel:

The heat treatment process for SAE/AISI 1018 steel involves four key stages, each contributing to the attainment of specific material properties:

Annealing:

Austenitizing at 870 to 900°C initiates the process, promoting a phase change in the steel.

Slow cooling follows, refining the grain structure and enhancing overall material properties

Normalizing:

The steel is reheated to a temperature range of 860 to 890°C.

Cooling in the air follows, further adjusting the microstructure for improved properties.

Stress Relieving:

Achieved by heating the steel to a temperature between 580 and 650°C.

Cooling in air alleviates internal stresses within the material.

Hardening:

Quenching, involving rapid cooling in oil or water, imparts increased hardness.

Tempering follows at 170 to 230°C, balancing hardness with desirable toughness.

Machining SAE/AISI 1018 Steel

Machining SAE/AISI 1018 steel demands skill and precision owing to its low carbon content. This alloy, comprised of iron, manganese, phosphorus, sulfur, and silicon, offers versatility due to its excellent weldability, formability, and ease of machining. Various machining operations, including turning, drilling, boring, milling, and tapping, can be carried out effectively.

To optimize machining processes, it is recommended to use high-speed cutting tools with an optimum hardness. This choice enhances tool life, ensuring efficiency and cost-effectiveness during machining operations. Notably, heat treatment is not advised for SAE/AISI 1018 steel, as it lacks additional heat-treatable alloying elements.

Adhering to good machining practices is crucial for achieving high-quality finished parts when working with this commonly used steel. Skilled handling, precision in tool selection, and adherence to recommended machining techniques contribute to successful and efficient machining processes for SAE/AISI 1018 steel.

Welding SAE/AISI 1018 Carbon Steel

Welding SAE/AISI 1018, a low-carbon steel, is a highly viable and cost-effective option. Low-alloy steels, including SAE/AISI 1018, provide an economical alternative, particularly in structures with less stringent requirements. Noteworthy for its remarkable strength and durability, this steel is well-suited for a spectrum of welding applications, ranging from major projects to everyday welding tasks.

Despite its relatively low carbon content, SAE/AISI 1018 exhibits excellent weldability, making it particularly advantageous for structural elements that necessitate extensive welding. Its combination of strength, toughness, and weldability positions SAE/AISI 1018 as an ideal choice for constructing components in diverse industries, including automotive and construction. Whether for major structural projects or routine welding jobs, SAE/AISI 1018 proves to be a reliable and versatile material, meeting the demands of various welding applications.

Conclusion

SAE/AISI 1018 steel stands out as a highly versatile material with a myriad of benefits, positioning it as an ideal choice for a wide range of industrial applications. From automotive components like gears and shafts to furniture frames, food production equipment, and various fasteners, bolts, springs, sprockets, crankshafts, pistons, and pins, this steel proves its worth. Its high tensile strength, coupled with excellent formability properties, makes it a reliable option.

Moreover, the ease of machining sets SAE/AISI 1018 apart from other steels, offering a practical solution for projects that require both strength and malleability. This comprehensive guide aimed to provide you with all the necessary information about SAE/AISI 1018 steel, empowering you to make informed decisions when selecting materials for your next project. With its diverse applications and advantageous properties, SAE/AISI 1018 steel stands as a valuable and dependable choice in the realm of metal alloys.

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