AISI 4340 steel (UNS G43400) is an ultra-high-strength, medium-carbon, low-alloy steel that combines deep hardenability, high ductility, toughness, and strength with high fatigue and creep resistance. It is unaffected by tempering and embrittlement exhibits good strength retention at elevated temperatures and is not susceptible to softening. In thin sections, this steel is air-hardened.
Introduction: The Robust Foundation of 4340 Steel
AISI 4340 is defined as a heat-treatable low alloy steel containing 0.8% Cr, 0.2% Mo, and 1.8% Ni as strengthening alloying elements. Compared to AISI 4140, it has higher strength and toughness and very good fatigue, wear, and atmospheric corrosion resistance. AISI 4340 is generally supplied in the quenched and tempered condition, with a tensile range of 930 – 1080 Mpa and a hardness of 280 – 320 HB. Pre-hardened and tempered 4340 can be further surface hardened by flame or induction Pre-hardened and tempered 4340 can be further surface hardened by flame or induction hardening and nitriding.
Chemical Composition: The Alchemy of Strength
The chemical composition of 4340 steel is shown in Table 1：
Table 1: Chemical Composition of 4340 Steel
| Element | Content (%) |
|---|---|
| Iron, Fe | 95.5 – 96.33 |
| Nickel, Ni | 1.65 – 2.00 |
| Chromium, Cr | 0.70 – 0.90 |
| Manganese, Mn | 0.60 – 0.80 |
| Carbon, C | 0.37 – 0.43 |
| Molybdenum, Mo | 0.20 – 0.30 |
| Silicon, Si | 0.15 – 0.30 |
| Sulfur, S | 0.040 |
| Phosphorus, P | 0.035 |
Mechanical Properties: Unveiling the Might
Mechanical properties, crucial in designing mechanical products, comprise commonly used indicators for metallic materials. In Table 2, the mechanical properties of 4340 steel are listed.
Table 2: Mechanical Properties of 4340 Steel
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
| Tensile Strength | 745 MPa | 108,000 psi |
| Yield Strength | 470 MPa | 68,200 psi |
| Hardness (Rockwell B) | 217 | – |
| Elongation at Break | 22% | – |
| Reduction of Area | 50% | – |
Applications: Where Strength Meets Precision
Exploring diverse applications showcases the adaptability of 4340 steel, widely utilized in various fields:
- Aerospace components: 4340 steel is well-designed and plays an important role in the manufacture of quality aerospace products.
- Landing gear: 4340 steel ensures robustness and reliability and is the material of choice for highly stressed landing gear components.
- Engine Components: From cylinders to crankshafts, the high fatigue strength of alloys makes them indispensable for core engine components.
- Crankshafts and axles: The through-hardening ability of alloys makes them ideal for the manufacture of durable crankshafts and axles.
Advantages of Otai Special Steel: Elevating the Standards
At OTAI Special Steel, excellence and reliability go hand in hand, and we are proud to offer 4340 steel that exceeds industry standards. Here are our strengths:
- Global presence: Our products are exported to more than 30 countries and meet a variety of standards, ensuring that our steel meets a wide range of needs.
- Trusted supplier: As a long-term supplier to TOP 500 companies such as ThyssenKrupp and China National Weapons Industry Corporation, we adhere to the highest quality standards.
- Cost-effectiveness: We are committed to reducing our distributors’ overall costs by 20 percent.
- Decades of experience: More than 20 years of pre-sales and after-sales service experience.
- Prompt response: Our after-sales service commitment includes a 2-hour response time to ensure that your queries are dealt with promptly.
Conclusion: Your Gateway to Strength and Reliability
In short, 4340 steel, is a material that possesses good strength. It can be used in several applications, both in aerospace and engineering.
Feel free to share your thoughts and experiences with 4340 Steel in the comments below. For any inquiries, collaborations, or to explore the world of premium steel, contact our team. We’re here to elevate your standards with the strength you can trust.
