SAE/AISI 3140 Alloy Steel (UNS G31400)
SAE/AISI 3140 is a nickel-chromium low-alloy steel valued for its excellent combination of strength, toughness, and wear resistance. It can be heat treated to reach various hardness levels, making it ideal for demanding engineering applications such as gears, axles, and power transmission components across multiple industries.
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| Chemical Composition | ||
|---|---|---|
| Element | Min | Max |
| Iron | 96.1% | 97.1% |
| Carbon | 0.38% | 0.43% |
| Chromium | 0.55% | 0.75% |
| Manganese | 0.70% | 0.90% |
| Nickel | 1.10% | 1.40% |
| Phosphorous | —— | 0.04% |
| Silicon | 0.15% | 0.35% |
| Sulfur | —— | 0.04% |
The following table provides a list of SAE/AISI 3140 properties in both SI and US customary/Imperial units.
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| Physical Properties | Metric |
|---|---|
| Density | 7850 kg/m3 |
| Mechanical Properties | Metric |
| Tensile Strength (Ultimate) | 790 MPa |
| Tensile Strength (Yield) | 520 MPa |
| Elongation at Break | 25% |
| Reduction of Area | 55% |
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 3140 Alloy Steel
| Advantages | Disadvantages |
|---|---|
| Good strength and toughness | Limited hardenability |
| Wear resistance | Moderate machinability |
| Good resistance to corrosion | Susceptible to cracking during welding |
| Can be heat treated to desired hardness levels | Requires careful heat treatment to avoid brittleness |
| Versatile and widely available | Higher cost compared to some plain carbon steels |
Applications of 3140 Alloy Steel
SAE/AISI 3140 is commonly used across mechanical and industrial sectors where strength, durability, and wear resistance are essential, including:
- Gears and Shafts: Good strength and wear resistance make it suitable for gears, shafts, and other power transmission components.
- Axles and Bolts: Medium carbon content combined with toughness makes it ideal for use in axles and high-strength bolts.
- Machine Components: Utilized in various machine parts, including crankshafts, connecting rods, and spindles.
- Forgings and Springs: Excellent heat-treatability enables use in forged crankshafts and high-performance springs.
- Wear-resistant Parts: Suitable for components exposed to abrasive or erosive environments due to its high wear resistance.