SAE/AISI 4150 Alloy Steel (UNS G41500)
SAE/AISI 4150 is a chromium-molybdenum alloy steel known for its high strength, outstanding hardenability, and good toughness. It is frequently chosen for applications requiring excellent wear resistance and mechanical performance under stress, making it ideal for gears, shafts, and load-bearing components across automotive and industrial sectors.
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| Chemical Composition | ||
|---|---|---|
| Element | Min | Max |
| Iron | 96.74% | 97.67% |
| Carbon | 0.48% | 0.53% |
| Chromium | 0.80% | 1.10% |
| Manganese | 0.75% | 1.00% |
| Molybdenum | 0.15% | 0.25% |
| Phosphorous | —— | 0.035% |
| Silicon | 0.15% | 0.30% |
| Sulfur | —— | 0.04% |
The following table provides a list of SAE/AISI 4150 properties in both SI and US customary/Imperial units.
Click on the button to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Density | 7850 kg/m3 |
| Mechanical Properties | Metric |
| Tensile Strength (Ultimate) | 731 MPa |
| Tensile Strength (Yield) | 380 MPa |
| Young’s Modulus (E) | 190 - 210 GPa |
| Bulk Modulus (K) | 140 GPa |
| Shear Modulus (G) | 80 GPa |
| Elongation at Break | 20% |
| Reduction of Area | 40% |
| Poisson’s Ratio (ν) | 0.27 - 0.30 |
| Brinell Hardness | 197 |
| Thermal Properties | Metric |
| Thermal Conductivity | 44.5 W/m·K |
| Specific Heat Capacity (Cp) | 470 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 1.3×10-5 1/°C |
| Electrical Properties | Metric |
| Electrical Conductivity | 4.23×106 S/m |
| Electrical Resistivity | 2.36×10-7 Ω·m |
The values in this table are approximate and can vary depending on various factors such as the specific manufacturing process and heat treatment applied to the alloy.
Advantages & Disadvantages of 4150 Alloy Steel
| Advantages | Disadvantages |
|---|---|
| High strength and hardness | Relatively low corrosion resistance |
| Good toughness and impact resistance | Challenging to machine after heat treatment |
| Excellent wear resistance | Susceptible to distortion during heat treatment |
| Good machinability in annealed state | Requires proper heat treatment for optimum properties |
| Versatile and widely available | Higher cost compared to low-carbon steels |
Applications of 4150 Alloy Steel
Due to its robust mechanical properties, 4150 steel is widely used in demanding engineering and industrial applications, including:
- Gears and Gear Shafts: High strength, hardness, and wear resistance make it suitable for gears and gear shafts used in machinery, automotive transmissions, and heavy-duty equipment.
- Axles and Shafts: The excellent combination of strength and toughness makes it a preferred choice for axles and shafts in automotive applications, such as truck axles, crankshafts, and axle shafts.
- Piston Rods: High strength, hardness, and wear resistance provide reliable performance for piston rods in hydraulic and pneumatic cylinders under heavy loads.
- Bolts and Fasteners: High tensile strength, toughness, and fatigue resistance make it ideal for bolts, studs, and fasteners in heavy machinery, construction equipment, and structural components.
- Tooling and Die Components: The alloy’s hardness, wear resistance, and machinability support its use in punches, dies, molds, and cutting tools across manufacturing, forging, and stamping industries.
- Heavy-Duty Machine Parts: Used in crankshafts, gears, couplings, and spindles requiring high strength, toughness, and resistance to wear and impact for reliable operation.
- Oil and Gas Industry Components: Suitable for drill collars, stabilizers, and shafts, where strength, toughness, and corrosion resistance are critical in harsh environments.
- Automotive Components: Used in steering systems, suspension parts, and transmission components that demand high strength, toughness, and long-term durability.