SAE/AISI E4340 Alloy Steel (UNS G43406)
SAE/AISI E4340 steel is a medium-carbon, low-alloy steel that is known for its toughness and strength. It is typically used in structural applications, such as aircraft landing gears.
| Chemical Composition | ||
|---|---|---|
| Element | Min | Max |
| Iron | 95.175% | 96.27% |
| Carbon | 0.38% | 0.43% |
| Chromium | 0.70% | 0.90% |
| Manganese | 0.65% | 0.85% |
| Molybdenum | 0.20% | 0.30% |
| Nickel | 1.65% | 2.0% |
| Phosphorous | 0.025% | |
| Silicon | 0.15% | 0.30% |
| Sulfur | 0.02% | |
The following table provides a list of SAE/AISI E4340 properties in both SI and US customary/Imperial units.
Click on the icon to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Density | 7850 kg/m3 |
| Mechanical Properties | Metric |
| Tensile Strength (Ultimate) | 745 MPa |
| Tensile Strength (Yield) | 470 MPa |
| Young’s Modulus (E) | 190 - 210 GPa |
| Bulk Modulus (K) | 140 GPa |
| Shear Modulus (G) | 80 GPa |
| Elongation at Break | 22% |
| Reduction of Area | 50% |
| Poisson’s Ratio (ν) | 0.27 - 0.30 |
| Brinell Hardness | 217 |
| Thermal Properties | Metric |
| Thermal Conductivity | 44.5 W/m·K |
| Specific Heat Capacity (Cp) | 470 J/kg·K |
| Coefficient of Thermal Expansion (αL) | 1.13×10-5 1/°C |
| Electrical Properties | Metric |
| Electrical Resistivity | 2.48×10-7 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 E4340 Alloy Steel
| Advantages | Disadvantages |
|---|---|
| High strength and toughness | Relatively high cost compared to carbon steels |
| Excellent wear resistance | Requires careful heat treatment for best results |
| Good hardenability | Prone to distortion during heat treatment |
| High fatigue resistance | Limited weldability |
| Good impact resistance | Susceptible to cracking if improperly heat treated |
| Wide range of heat treatment options | Requires skilled machining for complex shapes |
Applications of E4340 Alloy Steel
AISI E4340 steel finds application in various industries where high strength, toughness, and wear resistance are required. Some common applications of E4340 steel include:
- Aerospace Components: E4340 steel is used in the aerospace industry for manufacturing critical components such as gears, shafts, landing gear parts, structural components, and engine parts.
- Automotive and Racing Components: E4340 steel is employed in the automotive industry for applications that require high-performance and durability. It is utilized in manufacturing crankshafts, connecting rods, gears, camshafts, and other high-stress engine components. In racing applications, E4340 steel is favored for its ability to withstand extreme loads and vibrations.
- Oil and Gas Industry: E4340 steel is used in the oil and gas sector for components exposed to harsh environments and high-stress conditions. It is utilized in manufacturing drill collars, drill string components, gears, and shafts for downhole tools and equipment. The steel’s toughness and resistance to deformation make it suitable for demanding drilling and extraction operations.
- Power Transmission: E4340 steel is employed in the power transmission industry for manufacturing gears, shafts, and other components used in heavy machinery, gearboxes, and power generation equipment. The steel’s high strength and wear resistance ensure efficient power transfer and durability under demanding operating conditions.
- Tool and Die Making: E4340 steel is utilized in tool and die making applications where high strength and toughness are required. It is used for manufacturing punches, dies, forging dies, and various tooling components that are subjected to high loads and repeated impacts.
- General Engineering: E4340 steel finds application in various general engineering applications where high strength, hardness, and wear resistance are necessary. It can be used for manufacturing shafts, gears, axles, and other components in industrial machinery, agricultural equipment, and construction machinery.