SAE/AISI 4145 Alloy Steel (UNS G41450)
SAE/AISI 4145 is a low-alloy chromium-molybdenum steel known for its high fatigue strength, toughness, and ability to retain mechanical properties at elevated temperatures. It is widely used in demanding industries such as oil and gas, especially for components like drill collars, tool joints, and pipes that require durability under stress.
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| Chemical Composition | ||
|---|---|---|
| Element | Min | Max |
| Iron | 96.79% | 97.72% |
| Carbon | 0.43% | 0.48% |
| Chromium | 0.80% | 1.10% |
| Manganese | 0.75% | 1.10% |
| 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 4145 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 |
| Young’s Modulus (E) | 190 - 210 GPa |
| Bulk Modulus (K) | 140 GPa |
| Shear Modulus (G) | 80 GPa |
| Poisson’s Ratio (ν) | 0.27 - 0.30 |
| Brinell Hardness | 208 |
| Thermal Properties | Metric |
| Thermal Conductivity | 42.6 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 4145 Alloy Steel
| Advantages | Disadvantages |
|---|---|
| High strength and toughness | Relatively high cost compared to some other steels |
| Good resistance to wear and fatigue | Requires proper heat treatment for optimal properties |
| Excellent hardenability | Limited availability in certain regions |
| Corrosion resistance in various environments | Moderate weldability |
| Maintains mechanical properties at elevated temperatures |
Applications of 4145 Alloy Steel
SAE/AISI 4145 steel is widely used in energy and industrial sectors requiring strength, durability, and fatigue resistance, including:
- Oil Drilling Equipment: Extensively used in the production of drill collars, drill pipes, tool joints, and other components for oil drilling and exploration equipment.
- Downhole Tools: Employed in the manufacturing of downhole tools such as stabilizers, mud motor components, and subs.
- Wellhead and Christmas Tree Equipment: Wellheads and Christmas tree assemblies often utilize this alloy for various components such as valves, flanges, and connectors.
- Pipe and Tubing: Utilized for the production of high-strength, corrosion-resistant pipe and tubing used in oil and gas transportation.
- Automotive and Heavy Machinery Components: May find application in the manufacturing of automotive parts, such as axles, shafts, and gears.