ThePipingMart Blog Grades C45 Steel – Composition, Properties, and Uses

C45 Steel – Composition, Properties, and Uses

C45 Steel

Steel is used in numerous industrial applications for its strength, durability, and versatility. One such popular type of steel is C45 steel, a medium-carbon steel widely used in manufacturing and construction industries. In this blog post, we will discuss the composition, physical, and mechanical properties of C45 steel, along with its uses, hardness, and heat treatment.

C45 Steel Composition

C45 steel is a medium carbon steel that contains 0.45% carbon, which gives it high strength and hardness. It also has other elements such as Mn (1.0%), Si (0.4%), and small amounts of other elements. The composition of C45 steel makes it ideal for manufacturing components that require high strength, such as axles, gears, and shafts. It is also used for construction parts, such as bridges, and in the automobile and aerospace industries.

Carbon 0.42-0.50% Phosphorous 0.045% max
Manganese 0.50-0.80% Sulphur 0.045% max
Silicon 0.15-0.40%

C45 Steel Physical Properties

One of the physical properties of C45 steel is its density, which is approximately 7.85 g/cm³. It has a melting point of 1480°C, a thermal conductivity of 48 W/mK at room temperature, and an electrical conductivity of 23.5 W/(m-K) at 100°C. These properties make it an excellent choice for welding and heat treatment.

C45 Steel Mechanical Properties

Regarding mechanical properties, C45 steel has a tensile strength of 570-700 MPa and a yield strength of 330-460 MPa. Its elongation at break is 20%, and its impact strength is 50 J/cm2. These properties make it an ideal material for manufacturing components subjected to heavy loads and impacts.

Diameter d (mm) Thickness t (mm) 0.2 % proof stress (N/mm2) Tensile strength (N/mm2) Elongation A5 (%) Reduction Z (%)
<16 <8 min. 490 700-850 min. 14 min. 35
<17-40 <8<=20 min. 430 650-800 min. 16 min. 40
<41-100 <20<=60 min. 370 630-780 min. 17 min. 45

C45 Steel Uses

The uses of C45 steel are varied and widespread due to its strength and durability. It makes gears, axles, shafts, and other mechanical components that require high strength. It is also used in construction to build bridges and manufacture automobile and aerospace parts.

C45 Steel Hardness

The hardness of C45 steel is a critical factor to consider when selecting it for industrial applications. It is rated on the Rockwell hardness scale with a 170-210 HB range. This rating makes C45 steel hard enough to withstand heavy loads and impacts while remaining ductile and flexible.

C45 Steel Heat Treatment

Heat treatment of C45 steel involves quenching and tempering, which is a process of heating and cooling the steel to alter its physical and mechanical properties. This process significantly enhances the steel’s hardness, strength, and durability, making it more suitable for various industrial applications.


In conclusion, C45 steel is popular for manufacturing and construction due to its strength, durability, and versatility. Its composition, physical and mechanical properties, uses, hardness and heat treatment are essential when selecting it for industrial applications. Incorporating C45 steel as part of any industrial product ensures your product’s strength, durability, and overall quality.

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