• May 15th 2023

The world of steel is vast and complex, with countless varieties of alloys and compositions designed for specific applications. One such steel is AISI 1065, a high-carbon steel known for its excellent machinability and strength properties. This essay will delve into the world of AISI 1065 steel, specifically focusing on its equivalent materials. We will explore the chemical composition, mechanical properties, applications, and alternative materials, providing a comprehensive understanding of this essential material.

1. Introduction to AISI 1065 Steel

AISI 1065 steel is a high-carbon steel that belongs to the SAE-AISI family. The American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE) developed these numerical designations to simplify the identification of various steel grades. The AISI 1065 steel's specifications include excellent machinability, high strength, and good wear resistance, making it suitable for a wide range of applications.

1.1 Chemical Composition

The chemical composition of AISI 1065 steel is primarily composed of iron (Fe), with significant amounts of carbon (C), manganese (Mn), and small traces of silicon (Si), phosphorus (P), and sulfur (S). The approximate percentages for these elements are as follows:

  • Iron (Fe): 98.38 - 99%
  • Carbon (C): 0.60 - 0.70%
  • Manganese (Mn): 0.60 - 0.90%
  • Silicon (Si): ≤ 0.35%
  • Phosphorus (P): ≤ 0.04%
  • Sulfur (S): ≤ 0.05%

The high carbon content enhances the steel's hardness, strength, and wear resistance, while the manganese content improves the ductility and hardenability.

2. Mechanical Properties of AISI 1065 Steel

The mechanical properties of AISI 1065 carbon steel largely determine its suitability for various applications. These properties include tensile strength, yield strength, elongation, hardness, and impact resistance.

2.1 Tensile Strength

AISI 1065 steel exhibits high tensile strength, ranging between 650-880 MPa. Tensile strength is a measure of the steel's ability to withstand tensile or stretching forces without fracturing. This makes it suitable for applications requiring high strength and resistance to deformation.

2.2 Yield Strength

The yield strength of AISI 1065 steel is approximately 360 MPa. Yield strength is the stress at which a material starts to deform plastically, meaning it will not return to its original shape after removing the applied load. A higher yield strength indicates a material that is less prone to permanent deformation under load.

2.3 Elongation

AISI 1065 steel has an elongation percentage of around 10% in 50 mm. Elongation is a measure of the steel's ductility, or its ability to deform without breaking. This property is essential in applications where the material must endure bending, stretching, or other forms of deformation.

2.4 Hardness

The hardness of AISI 1065 steel, as measured by the Rockwell C Hardness scale, ranges from 64 to 66 HRC. This high hardness contributes to the steel's excellent wear resistance, making it ideal for components that experience significant friction and abrasion.

2.5 Impact Resistance

Although AISI 1065 steel has high strength and hardness, it has relatively low impact resistance due to its high carbon content. This means it is more prone to cracking or fracturing under sudden impact forces compared to lower carbon steels.

3. Applications of AISI 1065 Steel

AISI 1065 steel's unique combination of properties lends itself to a wide range of applications. Some common uses for this material include:

  • Springs: The high strength and hardness of AISI 1065 steel make it an excellent choice for manufacturing various types of springs, such as coil springs, leaf springs, and torsion bars.
  • Cutting tools: The wear resistance and strength of AISI 1065 steel make it suitable for manufacturing cutting tools like knives, shears, and chisels.
  • Gears: High strength and wear resistance also make AISI 1065 steel ideal for producing gears and other power transmission components.
  • Automotive components: Due to its excellent machinability and strength, AISI 1065 steel can be used to manufacture various automotive parts, including axles, shafts, and fasteners.

4. Equivalent Materials

While AISI 1065 steel is widely used and well-regarded, there are alternative materials with similar properties and applications. Some of these equivalent materials include:

4.1 EN C67S

EN C67S is a European high-carbon steel with comparable chemical composition and mechanical properties to AISI 1065 steel. Its high strength, hardness, and wear resistance make it a suitable alternative for applications like springs, cutting tools, and automotive components.

4.2 JIS S65C

JIS S65C is a Japanese high-carbon steel that shares many similarities with AISI 1065 steel. With a similar carbon content and comparable mechanical properties, JIS S65C is another viable alternative for applications requiring high strength and wear resistance.

4.3 GB 65Mn

GB 65Mn is a Chinese high-carbon steel that is equivalent to AISI 1065 steel in terms of composition and mechanical properties. This material is widely used in the production of springs, cutting tools, and automotive components, making it an appropriate substitute for AISI 1065 steel in many applications.

4.4 DIN CK67

DIN CK67 is a German high-carbon steel that exhibits similar properties to AISI 1065 steel. With its high strength, hardness, and wear resistance, DIN CK67 can be used interchangeably with AISI 1065 steel in many applications.

5. Qinghe Steel Supplier

Carbon Steel Pipe

Carbon steel piping is a durable material made from carbon steel, a steel alloy with iron and carbon. Qinghe Steel offers a range of carbon steel pipe to meet your application needs, including hard-to-find and custom sizes.

Carbon Steel Coil

Qinghe Steel is a professional steel coil supplier and is specialized in different types of steel coils with competitive price. 

Carbon Steel Sheet

Carbon steel blanks, flats, bars, plates and sheet stock from Qinghe Steel come in a variety of widths, lengths and thicknesses for your industrial applications. Uses range from machined parts, to cutting blades and knives, structural applications in construction, punches, dies, springs, and more.

Carbon Steel Bar and Rod

Carbon steel bar is stocked in flat, hexagonal, angle, round and, square at Qinghe Steel and we have an extensive range of cold rolled bar carbon steels – from low carbons, medium carbons, and up to high carbons.

Carbon Steel Profile

Qinghe Steel has extensive experience cold rolling and hot rolling carbon steel profiles of carbon steel grades to meet your customer's needs.

6. Summary

AISI 1065 steel is a high-carbon steel known for its excellent machinability, strength, and wear resistance. Its unique combination of properties leads to a wide range of applications, including springs, cutting tools, gears, and automotive components. The chemical composition of AISI 1065 steel primarily consists of iron, carbon, and manganese, with trace amounts of silicon, phosphorus, and sulfur.

The mechanical properties of AISI 1065 steel include high tensile strength (650-880 MPa), yield strength (approximately 360 MPa), elongation (around 10% in 50 mm), hardness (64 to 66 HRC), and relatively low impact resistance. These properties make it suitable for various applications requiring high strength and resistance to wear.

Several equivalent materials can be used as alternatives to AISI 1065 steel, including EN C67S, JIS S65C, GB 65Mn, and DIN CK67. These materials exhibit similar chemical compositions and mechanical properties, making them suitable substitutes in many applications.

Understanding the properties and applications of AISI 1065 steel and its equivalent materials is essential for selecting the right material for a given application. By considering factors such as strength, hardness, wear resistance, and machinability, engineers and manufacturers can make informed decisions about which material is best suited for their specific needs.

Always consult with us to ensure the chosen material is suitable for your specific application.