ThePipingMart Blog Grades 1045 Steel (AISI 1045) – Composition, Properties and Uses

1045 Steel (AISI 1045) – Composition, Properties and Uses

1045 Steel

1045 Steel is the most commonly used medium carbon steel. It has a wide variety of applications and can be heat treated for added strength. This guide will provide an overview of 1045 Steel, including its composition, chemical properties, mechanical properties, physical properties, uses, corrosion resistance, heat resistance and heat treatment.

1045 Steel Composition

AISI 1045 Steel is composed mostly of iron (Fe), with small amounts of other elements such as manganese (Mn), sulfur (S), phosphorus (P) and silicon (Si). The exact percentage of these elements can vary depending on the grade and type of steel.

Element Content
Carbon, C 0.420 – 0.50 %
Iron, Fe 98.51 – 98.98 %
Manganese, Mn 0.60 – 0.90 %
Phosphorous, P ≤ 0.040 %
Sulfur, S ≤ 0.050 %

1045 Steel Chemical Properties

Its composition determines the chemical properties of 1045 steel. It has a relatively high carbon content compared to other steels, which gives it excellent strength and hardness. It also has good ductility and machinability, making it ideal for many industrial applications such as gears and shafts.

1045 Steel Mechanical Properties

The mechanical properties of 1045 steel are determined by its composition and heat treatment process. The mechanical properties include yield strength, tensile strength, hardness and elongation. AISI 1045 steel is known for its high strength-to-weight ratio, which makes it suitable for many applications where weight is a concern, such as automotive components or construction materials.

Mechanical Properties Metric Imperial
Hardness, Brinell 163 163
Hardness, Knoop (Converted from Brinell hardness) 184 184
Hardness, Rockwell B (Converted from Brinell hardness) 84 84
Hardness, Vickers (Converted from Brinell hardness) 170 170
Tensile Strength, Ultimate 565 MPa 81900 psi
Tensile Strength, Yield 310 MPa 45000 psi
Elongation at Break (in 50 mm) 16.0 % 16.0 %
Reduction of Area 40.0 % 40.0 %
Modulus of Elasticity (Typical for steel) 200 GPa 29000 ksi
Bulk Modulus (Typical for steel) 140 GPa 20300 ksi
Poissons Ratio (Typical For Steel) 0.290 0.290
Shear Modulus (Typical for steel) 80 GPa 11600 ks

1045 Steel Physical Properties

The composition and heat treatment process determine the physical properties of 1045 steel. These include density, thermal conductivity and electrical resistivity. Its density is 7.85 g/cm3, which makes it slightly heavier than other steels but still light enough for many applications where weight is an issue, such as in the automotive industry or in construction materials. Its thermal conductivity is 43 W/mK which makes it an ideal material for transferring heat in various applications such as cookware or radiators while its low electrical resistivity makes it suitable for use in electrical components such as wires or wire harnesses.

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

1045 Steel Equivalent

ASTM A29/29M C Si Mn P S
1045 0.43~0.50 / 0.60~0.90 ≤0.040 ≤0.050
DIN W-Nr C Si Mn P S
1.1191/CK45 0.42~0.50  ≤0.40 0.50~0.80 ≤0.035 ≤0.035
GB/T C Si Mn P S
45 0.42~0.50 0.17~0.37 0.50~0.80 ≤0.035 ≤0.035
BS C Si Mn P S
080M46 0.42~0.50 ≤0.40 0.50~0.80 ≤0.035 ≤0.035
S45C 0.42~0.48 0.15~0.35 0.60~0.90 ≤0.030 ≤0.030

1045 Steel Uses

The most common use of 1045 steel is in manufacturing parts that require high strength but not necessarily high wear resistance, such as gears and shafts or automotive components like axles and crankshafts. It can also be used in construction materials due to its high strength-to-weight ratio making it suitable for load-bearing structures like bridges or buildings with large spans between supports where weight needs to be kept low, but strength needs to remain high.

Corrosion Resistance

The corrosion resistance of 1045 steel depends on its composition. Still, it generally offers good corrosion resistance when compared to other steels thanks to its high chromium content, which forms a thin protective layer on the surface, preventing oxidation from occurring even when exposed to harsh environments like salt water or chemicals like acids or bases .

Heat Resistance

The heat resistance of 1045 steel depends on its composition. Generally, it offers good thermal stability when compared to other steels due to its relatively low carbon content combined with higher levels of chromium which helps prevent oxidation at elevated temperatures up to 900°C (1650°F).

Heat Treatment

Heat treating can be used to increase the strength and hardness of 1045 steel without significantly impacting its ductility or machinability, making it an ideal choice for many industrial applications that require both strength and flexibility at elevated temperatures up to 900°C (1650°F).


Machining is easy with this type of steel due to its high machinability rating. It is much easier and faster to cut than more brittle materials like aluminium or bronze alloys.


1045 Steel is a multi-purpose carbon steel that can be used for any industrial application due to its strength, hardness and heat resistance properties. It has a good composition for strength and ductility and is suitable for heat treatment to increase strength without significantly impacting machinability. It also has good corrosion resistance, which makes it ideal for use in exposed environments such as chemicals or salt water. Finally, it has good thermal stability, making it ideal for transferring heat in some applications such as cookware or radiators. Overall,1045 Steel is one of the most versatile carbon steel available today, with various uses from automotive components to bridges and buildings.

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