AISI E4340 Steel, heat treated, fatigue tested

AISI E4340 Steel, heat treated, fatigue tested Product Information -:- For detailed product information, please contact sales. -: AISI E4340 Steel, heat treated, fatigue tested Synonyms -:- For detailed product information, please contact sales. -:

AISI E4340 Steel, heat treated, fatigue tested Product Information -:- For detailed product information, please contact sales. -: ## **Technical Data Sheet: AISI 4340 (UNS G43400) Steel - Heat Treated & Fatigue Characterized Grade** ### **1. Product Overview** This specification defines **AISI 4340 alloy steel in a fully heat-treated condition with verified fatigue performance data**. This product undergoes controlled quenching and tempering (typically to high strength levels) followed by rigorous fatigue testing, making it a premium-grade material for **safety-critical, dynamically loaded components**. The inclusion of certified fatigue data (S-N curves) provides engineers with reliable design inputs for infinite-life or finite-life applications, reducing validation time and risk. **Core Value Proposition:** * **Design-Ready Data:** Supplied with validated fatigue strength parameters (e.g., endurance limit), enabling precise and efficient component design. * **Guaranteed Performance Consistency:** The additional fatigue testing ensures the heat treatment and material quality produce predictable, high-cycle fatigue performance. * **Risk Mitigation:** Ideal for applications where fatigue failure is the primary design constraint, offering higher confidence than standard mill test reports. --- ### **2. Standard Chemical Composition (Weight %)** Composition adheres to stringent AISI 4340 standards, often with tighter controls on impurities (S, P) and trace elements (O, N) to enhance fatigue crack initiation resistance. | Element | Content (%) | Role in Fatigue Performance | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.38 - 0.43 | Provides matrix strength for fatigue resistance | | **Manganese (Mn)**| 0.60 - 0.80 | Enhances hardenability for uniform properties | | **Silicon (Si)** | 0.15 - 0.35 | Increases strength; can be optimized for cleanliness | | **Nickel (Ni)** | 1.65 - 2.00 | Significantly improves fracture toughness, retards crack growth | | **Chromium (Cr)** | 0.70 - 0.90 | Improves hardenability and corrosion/oxidation resistance | | **Molybdenum (Mo)**| 0.20 - 0.30 | Enhances tempering resistance and reduces susceptibility to temper embrittlement | | **Sulfur (S)** | ≤ 0.015 (Typ.) | **Very low** to minimize inclusion content (initiation sites) | | **Phosphorus (P)** | ≤ 0.015 (Typ.) | **Very low** to reduce grain boundary embrittlement | | **Gaseous Elements**| Tightly Controlled | Low Oxygen & Nitrogen for improved cleanliness | --- ### **3. Mechanical & Physical Properties** *Typical properties after heat treatment to a high-strength condition (e.g., oil quenched and tempered at ~425-480°C / 800-900°F). Fatigue data is derived from rotating beam or axial tests on polished specimens.* | Property | Typical Value | Test Standard & Condition | | :--- | :--- | :--- | | **Tensile Strength** | 1550 - 1750 MPa (225 - 255 ksi) | ASTM E8 | | **Yield Strength (0.2%)** | 1380 - 1580 MPa (200 - 230 ksi) | ASTM E8 | | **Elongation** | 10% - 14% | ASTM E8 | | **Reduction of Area** | 40% - 50% | ASTM E8 | | **Hardness** | 44 - 48 HRC | ASTM E18 | | **Fracture Toughness (K_IC)** | 60 - 80 MPa√m | ASTM E399 | | **Modulus of Elasticity** | 205 GPa (29.7 x 10⁶ psi) | - | | **Fatigue Endurance Limit** | **~550 - 650 MPa** (R=-1) | **Polished specimen**, ASTM E466 | | **Fatigue Strength at 10⁶ cycles** | **~500 - 600 MPa** (R=0.1) | **Notched specimen** (Kt~3), ASTM E606 | | **Fatigue Crack Growth Rate (da/dN)** | Characterized per Paris' Law | ASTM E647 | **Key Fatigue Note:** The **endurance limit is highly sensitive to surface finish, residual stress, and part geometry**. The provided data is for laboratory specimens. **Derating factors must be applied** for actual components based on their surface condition (machined, ground, shot-peened) and stress concentrations. --- ### **4. Heat Treatment & Microstructural Basis** The fatigue-optimized heat treatment is critical: 1. **Austenitizing:** 830-870°C (1525-1600°F) followed by oil quenching to form a uniform, fine martensitic structure. 2. **Tempering:** Typically in the range of **425-480°C (800-900°F)** to achieve the optimal combination of high strength and toughness. 3. **Optional Enhancements:** This grade is an ideal candidate for **shot peening** (induces compressive surface stress) and **superfinishing** to dramatically improve *in-service* fatigue life beyond baseline data. --- ### **5. Target Applications** This material is specified for the most demanding applications where fatigue is the dominant failure mode. * **Aerospace:** * **Landing Gear:** Axles, torsion links, pistons. * **Rotary Wing:** Helicopter rotor mast, hub components. * **Jet Engine:** Turbine shafts, discs (subject to specific grades). * **Flight Control:** Critical actuator components. * **High-Performance Automotive & Racing:** * **Formula 1 / IndyCar:** Connecting rods, crankshafts, suspension pushrods. * **Top Fuel Dragsters:** Supercharger drive components. * **Oil & Gas Drilling:** * **Drill String Components:** Tool joints, cross-overs in high-cycle service. * **Downhole Tools:** Mud motor drives, agitator shafts. * **High-Cycle Industrial Machinery:** * **Printing Press:** Rolls and shafts. * **Textile Machinery:** High-speed spindles. * **Hydraulic Systems:** Piston rods for high-pressure pumps. --- ### **6. International Standards & Procurement Guidance** This is a **performance-specified product** beyond standard material grades. | Standard / Aspect | Guidance | | :--- | :--- | | **Base Material Standard** | **AMS 6414** (Steel, Bars, Forgings, and Tubing 0.40Cr - 1.8Ni - 0.25Mo - 0.43C (4340)) is the most relevant **Aerospace Material Specification**, often invoked for fatigue-critical parts. | | **Heat Treat Standard** | **AMS 2759/1** (Aerospace Heat Treatment) typically governs the process. | | **Fatigue Testing Standards** | **ASTM E466** (Force-Controlled Fatigue), **ASTM E606** (Strain-Controlled Fatigue), **ASTM E647** (Crack Growth Rate). | | **Procurement Specification** | Must be custom-defined, including:
1. **Base Material:** AMS 6414 or equivalent.
2. **Heat Treatment:** Required ultimate/yield strength or tempering parameters.
3. **Cleanliness:** Inclusion rating per **ASTM E45** (e.g., A≤B1, C≤1).
4. **Fatigue Data Requirement:** Specify test parameters (R-ratio, frequency, surface finish on specimen, number of samples) and required output (S-N curve, endurance limit at 10⁷ cycles). | | **European Equivalent** | **34CrNiMo6 (1.6582) + QT + Special Cleanliness** + Fatigue Testing. A proprietary standard like **DBL 8541** (Daimler) may be referenced. | **Essential Consideration:** Purchasing "fatigue-tested" 4340 involves a **technical dialogue with the mill or processor** to define the exact test parameters, acceptable data scatter, and certification requirements. It is a premium product with a significantly higher cost than standard heat-treated 4340. -:- For detailed product information, please contact sales. -: AISI E4340 Steel, heat treated, fatigue tested Specification Dimensions Size： Diameter 20-1000 mm Length <6248 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: AISI E4340 Steel, heat treated, fatigue tested Properties -:- For detailed product information, please contact sales. -:

Applications of AISI E4340 Steel, heat treated, fatigue tested -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI E4340 Steel, heat treated, fatigue tested -:- For detailed product information, please contact sales. -:

Packing of AISI E4340 Steel, heat treated, fatigue tested -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2719 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition