ThePipingMart Blog Grades SAE/AISI 5115 Alloy Steel (G51150)- Composition, Properties and Uses

SAE/AISI 5115 Alloy Steel (G51150)- Composition, Properties and Uses

SAE/AISI 5115 Steel

AISI 5115 is a low-alloy steel containing manganese, molybdenum, and chromium. 5115 Alloy Steel is popular for its toughness, wear resistance, and strength. G51150 steel is often used in automotive parts, bearings, shafts, gears, and more. Let’s take a closer look at the uses of SAE/AISI 5115, its corrosion resistance, heat resistance, heat treatment machining techniques, and welding capabilities.

AISI 5115 Composition

Element Weight %
C  0.13-0.18
Mn  0.70-0.90
P  0.035 (max)
S  0.04 (max)
Si  0.15-0.30
Cr  0.70-0.90

AISI 5115 Physical Properties

Physical Properties Metric English Comments
Density 7.85 g/cc 0.284 lb/in³

AISI 5115 Mechanical Properties

Mechanical Properties Metric English Comments
Tensile Strength, Ultimate 780 – 1080 MPa
@Thickness 30.0 mm
113000 – 157000 psi
@Thickness 1.18 in
Case Hardened
880 – 1230 MPa
@Thickness 16.0 mm
128000 – 178000 psi
@Thickness 0.630 in
Case Hardened
Tensile Strength, Yield 590 MPa
@Thickness 30.0 mm
85600 psi
@Thickness 1.18 in
Case Hardened
600 MPa
@Thickness 16.0 mm
87000 psi
@Thickness 0.630 in
Case Hardened
Elongation at Break 10 %
@Thickness 30.0 mm
10 %
@Thickness 1.18 in
Case Hardened
Modulus of Elasticity 200 GPa 29000 ksi Typical of Alloy Steel
Poissons Ratio 0.29 0.29 Typical of Alloy Steel

AISI 5115 Thermal Properties

Thermal Properties Metric English Comments
CTE, linear 12.0 µm/m-°C 6.67 µin/in-°F Typical of Alloy Steel
Specific Heat Capacity 0.470 J/g-°C 0.112 BTU/lb-°F Typical of Alloy Steel
Thermal Conductivity 52.0 W/m-K 361 BTU-in/hr-ft²-°F Typical of Alloy Stee

AISI 5115 Uses

SAE/AISI 5115 steel has excellent strength and wears resistance properties which make it great for high-stress applications. It is commonly used to manufacture car parts such as axles, crankshafts, bearings, gears, and shafts. This type of steel is also frequently used for tools like hammers and wrenches due to its good machinability. Additionally, SAE/AISI 5115 can be used in the construction industry for structural components like beams or columns because it offers superior weldability characteristics.

Corrosion Resistance

SAE/AISI 5115 steel has good corrosion resistance but not as much as stainless steel because it does not contain nickel or chromium. In order to increase its corrosion resistance, you can use galvanizing treatments or coatings such as paint to protect the surface from rust or other forms of oxidation.

Heat Resistance

The heat resistance of this type of steel depends on the amount of carbon present in the alloy – the higher the carbon content, the higher its heat resistance will be. However, even with a high carbon content, this material still cannot withstand temperatures above 600°C (1110°F). It should be noted that prolonged exposure to elevated temperatures can significantly reduce its mechanical properties over time, so it’s important to monitor these values regularly if you plan on using this material in an application that requires high-temperature stability.

Heat Treatment

SAE/AISI 5115 can be heat treated by heating the material up to 845°C (1550°F) followed by air cooling or oil quenching depending on your desired hardness level(s). Higher temperatures produce a softer material, while lower temperatures result in harder materials with improved wear resistance characteristics. Additionally, this material can also be annealed by heating between 650-750°C (1200-1380°F) followed by slow cooling, which helps restore some ductility after hardening processes have been applied previously.


This type of steel is relatively easy to machine so long as proper cutting speeds are used during operations, thanks to its moderate hardening rate compared with other types of steel available today. Common machining operations include turning, drilling, boring, reaming tapping, milling, etc. Additionally, since this alloy has good formability, you’re able to perform sheet metal forming operations without too much difficulty either!


SAE / AISI 5115 is easily weldable using common arc welding methods such as gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), shielded metal arc welding (SMAW), flux cored arc welding (FCAW), etc. When welding this material, preheat and post-heat treatments are usually required in order to restore optimal mechanical properties after completion – these steps can help minimize distortion during fabrication processes too!


In conclusion, SAE / AISI 5115 has many beneficial properties that make it ideal for many industrial applications such as automotive parts bearing shafts, gear tools, structural components, etc. Furthermore, this type of steel has good corrosion resistance, although it should still be protected from rust oxidation if necessary due to its lack of nickel & chromium content; additionally, it’s capable of withstanding temperatures up to 600°C (1110°F) while having easy machinability weldability & formability characteristics all making it an excellent choice when looking for reliable materials!

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SAE/AISI 5115 Alloy Steel (G51150)- Composition, Properties and Uses

by harsh jain time to read: 3 min