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Use and mystery of 1045 carbon steel

1045 carbon steel is a very widely used material in the industrial sector, it is praised for its outstanding strength, durability and versatility. This steel has a carbon content of about 0.45%, which classifies it as medium carbon steel. The basic composition of 1045 carbon steel consists of 98.51% to 98.98% iron, 0.60% to 0.90% manganese, and small amounts of silicon and phosphorus. The combination of these ingredients makes 1045 carbon steel widely used in many different industries. For example, it can be used to manufacture components such as gears, bolts, studs and axles, all of which require the high tensile strength and good workability offered by 1045 carbon steel.

The production process of 1045 carbon steel is carefully designed, first melting iron with carbon and other alloying elements at high temperatures, and then forming the metal through processes such as rolling or forging. For those industries looking for reliable materials to use in their products, it is important to understand the properties and applications of 1045 carbon steel. This paper will further discuss the characteristics, chemical composition, potential advantages and disadvantages of 1045 carbon steel.

What is 1045 carbon steel?

1045 carbon steel, also known as AISI 1045 steel, is a medium carbon steel alloy known for its specific carbon content of about 0.45%, strength, and durability. In addition to carbon, it also contains other elements such as manganese, phosphorus, sulfur and silicon, the addition of which gives 1045 carbon steel its unique mechanical properties. 1045 carbon steel has a body-centered cubic (BCC) crystal structure, and its carbon content has a significant effect on its overall strength. For more information on carbon steel, please refer to the relevant metal guide.

What is the use of 1045 carbon steel?

1045 carbon steel has a wide range of applications in many industrial fields. Its high tensile strength and good processing properties make it suitable for the manufacture of various parts. For example, gears, bolts, studs, axles, crankshafts, and mechanical parts are common applications for 1045 carbon steel. In addition, it is used to manufacture products such as hydraulic shafts, couplings and agricultural machinery that require robustness and impact resistance. 1045 carbon steel strikes a good balance between economy and performance such as strength, workability and wear resistance, making it the material of choice for many applications, including blades, cutting tools and those industrial tools that need to resist wear. The versatility and reliable performance of 1045 carbon steel make it very popular in the manufacturing and engineering industries.

How is 1045 carbon steel made?

1045 carbon steel is usually produced by the basic oxygen furnace (BOF) or electric arc furnace (EAF) method. In the production process, iron is first melted with the participation of alloying elements such as carbon and manganese. Subsequently, the molten metal is adjusted to achieve the desired chemical composition. After determining the final chemical composition, the steel is cast into various shapes, such as ingot or billet. The casting process of billets is usually carried out using a continuous casting machine (CCM). These forms are then transformed into the desired final product by methods such as hot rolling or forging.

What is the chemical composition of 1045 carbon steel?

The chemical composition of carbon steel mainly includes carbon, manganese, and a small amount of phosphorus and sulfur. The chemical composition of 1045 carbon steel can be summarized as follows:

Carbon (C) : 0.45%

Manganese (Mn) : 0.60-0.90%

Phosphorus (P) : Maximum 0.035%

Sulfur (S) : up to 0.035%

Silicon (Si) : up to 0.35%

Iron (Fe) : the remainder

The proportions and combinations of these elements give 1045 carbon steel its unique physical and chemical properties, enabling it to meet the needs of a wide range of industrial applications.







<= 0.040 %


<= 0.050 %


98.51 – 98.98 %

1045 carbon steel is a medium carbon steel, its carbon content is about 0.45%. This carbon content gives 1045 carbon steel a range of performance characteristics that are useful in many industrial applications.

First, 1045 carbon steel has a moderate carbon content, which makes it achieve a good balance between strength and toughness. This balance means that 1045 carbon steel can withstand a certain amount of force while maintaining a certain degree of plasticity and toughness, and is not easy to break. This is important for tools and parts that require both hardness and toughness.

Secondly, 1045 carbon steel can be further improved by heat treatment. Heat treatment is a process in which the microstructure and properties of metals are changed by heating and cooling. For 1045 carbon steel, heat treatment can increase its hardness, making it more suitable for manufacturing tools, molds and other tools that require high hardness.

In addition, due to the carbon content of 1045 carbon steel, its mechanical properties are at a moderate level. This means that it is neither too brittle nor too weak, so during the design and manufacturing process, engineers can adjust its performance as needed to suit different application scenarios.

In general, 1045 carbon steel has a wide range of applications in various industrial fields because of its moderate carbon content, good balance of strength and toughness, and the performance that can be improved by heat treatment. Whether as a tool steel or a structural steel, 1045 carbon steel can meet a variety of engineering needs and demonstrate its unique value.



7.87 g/cm³

Yield Strength

450-560 MPa


170-210 HB



Tensile strength

570 - 700 Mpa

Elongation at break (in 50mm)


Electrical conductivity


1045 carbon steel is a medium carbon content of steel, its carbon content is about 0.45%, this carbon content makes it in the annealed state has a good workability. In industry standards, the processability rating is a quantitative assessment of how easy a material is to process. For 1045 carbon steel, its machinability rating in the annealed state is approximately 65%, which means that it is one of those materials that is relatively easy to cut, mill or otherwise machine.

The machinability rating is determined by a comprehensive assessment of the material's cutting force, surface roughness, tool wear, and cutting temperature. The reason why 1045 carbon steel has good machinability is that its hardness and strength reach a moderate level after annealing treatment, neither too hard to cause tool wear too fast, nor too soft to cause too much chip deformation during processing.

In order to ensure that 1045 carbon steel can maintain its good machinability during processing, it is usually necessary to perform appropriate heat treatment. This involves heating the steel to a certain temperature and then cooling it at a controlled rate to obtain the desired microstructure and properties. The heat treatment process can affect the hardness, toughness and workability of the steel and must therefore be carefully controlled to ensure the best results.

The thermal properties of 1045 carbon steel refer to its behavior and characteristics under the action of heat. Its thermal conductivity is about 51.9W /m·K, which is a measure of the material's ability to conduct heat. In contrast, 304 stainless steel has a lower thermal conductivity of 16.8 W/(m·K), which indicates that 1045 carbon steel is more efficient at transferring heat. The high thermal conductivity makes 1045 carbon steel suitable for applications where good heat dissipation properties are required.

In addition, the specific heat capacity of 1045 carbon steel is about 486 J/kg·K, which is the energy required to increase the temperature of the material by one degree Celsius per unit mass. This parameter is important for designing heat exchange systems and predicting temperature changes in materials during heating or cooling.


Thermal Conductivity

51.9 W/m·K

Specific Heat Capacity

486 J/kg·K

Melting Point

1510 °C (2750 °F)

1045 carbon steel is a common engineering material, widely used in a variety of industrial fields. The diversity of this material is that it can be processed into different forms to suit different application needs. The following are some common forms of 1045 carbon steel materials and their characteristics:


1045 carbon steel sheet is known for its thin, flat form, which provides moderate strength and good machinability, while also having moderate weldability. Such sheets typically contain about 0.45% carbon, as well as trace elements such as manganese, phosphorus, and sulfur, which together give the material its characteristic properties. In the annealed state, 1045 carbon steel plate is composed of ferrite and pearlite structure, which makes the material have good strength and toughness. 1045 carbon steel plate has a wide range of applications in manufacturing, automotive manufacturing, construction, tool making, agriculture, industrial machinery, and the oil and gas industry.


The strength, machinability and wear resistance of 1045 carbon steel bars are mainly determined by their chemical composition and metallurgical properties, not just their shape. Nevertheless, solid cylindrical bars are widely used because of their ease of handling, machining, and installation. The cylindrical shape of the 1045 carbon steel rod provides many advantages in practical applications, such as easy fitting and joining. Its annealed structure is also composed of ferrite and pearlite, which provides the material with the necessary strength and toughness. 1045 carbon steel rods can be used to make shafts, gears, bolts, studs and other mechanical parts.


The main difference between sheet and steel is size. Steel products with a width of more than 8 inches are considered plates, while those with a width of less than 8 inches are considered flat steel products. 1045 carbon steel plates and bars are specific types of steel with carbon as the main component, and their logo "1045" indicates the content of carbon. 1045 carbon steel has high strength, good machinability and moderate weldability. AISI 1045 is an ordinary carbon steel containing 0.45% carbon, manganese, phosphorus, sulfur, and other trace elements. Its annealed structure has good toughness and impact resistance, and is suitable for manufacturing construction equipment, industrial machinery parts and mechanical frames.

Hot Rolling:

Hot rolling is a manufacturing process used to produce hot rolled 1045 carbon steel for a variety of industrial uses. This process produces a material with a scaly surface finish. Compared with cold-drawn or cold-rolled forms of steel, hot-rolled 1045 steel has better ductility, toughness and machinability. The automotive industry, construction and machinery manufacturing industries use hot-rolled 1045 steel to produce shafts, gears, axles and structural components.


Annealing is a heat treatment process that aims to change the microstructure and grain size of a material. By heating the material to a specific temperature, the material crystallizes, resulting in larger grains. If the material is in the martensitic phase before annealing, it will no longer remain in that phase after annealing. However, the distribution of pearlite and ferrite in the material may change while the total amount remains the same. Annealing is popular in various heat treatment techniques because it increases the ductility and reduces the hardness of materials. 1045 carbon steel in the annealing process, through heat treatment to eliminate the internal stress, improve the machinability. Steels in the annealed state exhibit better machinability, improved dimensional stability and reduced hardness.

Cold drawing:

1045 carbon steel after cold drawing or cold working will undergo plastic deformation above the recrystallization temperature, resulting in strain hardening. This reduces ductility while increasing yield strength and ultimate tensile strength compared to materials in the annealed state. The microstructure of cold-drawn 1045 steel is mainly composed of ferrite and pearlite, but its microstructure will show the characteristics of deformation. This manufacturing process improves the mechanical properties, surface quality and dimensional accuracy of the material, making it suitable for applications that require high strength, tight tolerances and excellent surface quality, such as automotive parts, axles and precision mechanical components.

What Are Equivalents of 1045 Carbon Steel?

CountryEquivalent Name

United States

AISI 1045

European Union

C45E or Ck45


1.1191 or C45E

United Kingdom

080M46 or 43A


S45C or S48C


45# or 45B

Advantages of using 1045 carbon steel include:

Excellent mechanical properties: 1045 carbon steel offers excellent tensile strength and hardness, which makes it ideal for harsh environments that require materials to withstand heavy loads and high pressures.

Ease of processing: This steel can be easily processed into different shapes and sizes, which means that manufacturers can meet complex design needs with an efficient production process.

Good weldability: AISI 1045 carbon steel exhibits good weldability when appropriate joining techniques are used, which is an important advantage for projects where structures need to be constructed by welding.

Advantages of microstructure: 1045 carbon steel is known for its ferrite and pearlite microstructure, which is composed of alternating ferrite and cementite (iron carbide), helping to improve its wear resistance. The carbides in the pearlite structure provide enhanced wear resistance to the steel, making it particularly suitable for the manufacture of parts that need to withstand wear and friction.

However, there are some drawbacks to using 1045 carbon steel:

Low corrosion resistance: 1045 carbon steel is not very resistant to corrosion in harsh environments and may require additional protective coatings or regular maintenance to prevent corrosion.

Limited heat treatment hardening capacity: Compared to other types of steel, 1045 carbon steel's ability to increase hardness through heat treatment is limited, which may limit its use in applications that require extremely high hardness.

Heat treatment or welding risks: If heat treatment or welding techniques are not applied properly, 1045 carbon steel parts may crack or deform.

Cost considerations: While 1045 carbon steel is not considered a high cost material compared to some specialty steels, it can cost more than lower grade carbon steel. The cost of steel is affected by a number of factors, including quality, availability, market demand, and the specific requirements of the project.

1045 carbon steel and A514 steel difference:

The main difference between 1045 carbon steel and A514 steel (also known as "T1") is their composition and strength. A514 steel is a high-strength, low-alloy steel that contains specific alloying elements, such as carbon, chromium and manganese, which give it greater strength and hardness and is commonly used in structural applications. With a carbon content of 0.45%, 1045 carbon steel is mainly used for general purpose applications, and its strength and hardness are relatively low, but still able to meet a wide range of industrial needs.


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