AISI 4140 Steel, oil quenched

AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] Product Information -:- For detailed product information, please contact sales. -: AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] Synonyms -:- For detailed product information, please contact sales. -:

AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] Product Information -:- For detailed product information, please contact sales. -: # **AISI 4140 Steel (Quenched & Tempered) Product Specification** ## **1. PRODUCT IDENTIFICATION & PROCESS** **Product:** AISI 4140 Alloy Steel Round Bar **Condition:** Oil Quenched and Tempered (Fully Heat Treated) **Diameter:** 13 mm (0.5 inch) **Heat Treatment Specification:** - **Austenitizing:** 845°C (1550°F) - **Quenching:** Oil quench (rapid agitation) - **Tempering:** 540°C (1000°F), followed by air cooling **Material State:** This product is supplied in its final heat-treated condition, ready for precision machining, grinding, or direct use. The combination of oil quenching and tempering at 540°C produces an optimal balance of high strength, good toughness, and excellent fatigue resistance for this specific diameter. ## **2. CHEMICAL COMPOSITION** | Element | Composition Range (% by weight) | Metallurgical Function in Q&T State | | :--- | :--- | :--- | | **Carbon (C)** | 0.38 - 0.43 | Forms martensite during quenching; determines maximum achievable hardness and strength. Fine carbides precipitate during tempering at 540°C. | | **Manganese (Mn)** | 0.75 - 1.00 | Enhances hardenability significantly; ensures full through-hardening of 13mm diameter in oil quench. Contributes to solid solution strengthening. | | **Phosphorus (P)** | ≤ 0.035 | Residual impurity; strictly controlled to prevent temper embrittlement. | | **Sulfur (S)** | ≤ 0.040 | Residual impurity; kept low for good transverse properties. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; provides solid solution strengthening and improves tempering resistance. | | **Chromium (Cr)** | 0.80 - 1.10 | **Key alloying element.** Increases hardenability, forms stable (Cr,Fe)₇C₃ carbides during tempering, enhancing wear resistance and secondary hardening at 540°C. | | **Molybdenum (Mo)** | 0.15 - 0.25 | **Critical for this application.** Prevents temper embrittlement at 540°C, increases high-temperature strength, and enhances hardenability for consistent through-hardening. | **Carbon Equivalent (CET) for Weldability:** ~0.75-0.85 (Indicates poor weldability in this hardened condition) ## **3. MICROSTRUCTURE & HARDENABILITY** **Microstructure:** Fine, uniform **tempered martensite** with finely dispersed alloy carbides. **Prior Austenite Grain Size:** ASTM 7-9 (fine grain, typical for this heat treatment) **Hardenability:** Excellent for 13mm diameter. Oil quenching from 845°C produces virtually 100% martensite throughout the cross-section prior to tempering, as confirmed by Jominy testing (typically J1.5 = 55-60 HRC as-quenched). ## **4. MECHANICAL PROPERTIES (TYPICAL FOR 13mm ROUND)** *All values are longitudinal properties unless otherwise specified.* | Property | Typical Value | Test Standard | | :--- | :--- | :--- | | **Ultimate Tensile Strength** | 1080 - 1200 MPa (157,000 - 174,000 psi) | ASTM A370 | | **Yield Strength (0.2% Offset)** | 950 - 1050 MPa (138,000 - 152,000 psi) | ASTM A370 | | **Elongation (in 50mm / 4D)** | 15% - 18% | ASTM A370 | | **Reduction of Area** | 50% - 55% | ASTM A370 | | **Hardness** | 32 - 36 HRC (302 - 327 HB) | ASTM E18 / E10 | | **Charpy V-Notch Impact (Room Temp)** | 25 - 40 J (18 - 30 ft-lb) | ASTM E23 | | **Modulus of Elasticity** | 205 GPa (29,700 ksi) | - | | **Fatigue Strength (Rotating Beam)** | ~550 - 600 MPa (80,000 - 87,000 psi) | - | ## **5. PHYSICAL PROPERTIES** | Property | Value / Condition | | :--- | :--- | | **Density** | 7.85 g/cm³ (0.284 lb/in³) | | **Melting Point** | ~1416°C (2580°F) | | **Thermal Conductivity** | 42.6 W/m·K @ 100°C | | **Coefficient of Thermal Expansion** | 11.2 µm/m·°C (20-100°C) | | **Electrical Resistivity** | 0.22 µΩ·m @ 20°C | | **Magnetic Properties** | Ferromagnetic | ## **6. TARGET APPLICATIONS** This specific product (13mm Q&T round) is engineered for high-stress, precision components requiring maximum strength-to-size ratio: * **Precision Shafts & Axles:** Automotive transmission shafts, pump shafts, spindle shafts in machinery * **High-Strength Fasteners:** Special bolts, studs, pins, and connectors in aerospace and automotive systems * **Hydraulic & Pneumatic Components:** Piston rods, cylinder barrels, valve stems * **Tooling & Machining:** Lathe centers, drill bushings, fixture pins, die components * **Agricultural & Off-Road:** Pivot pins, linkage arms, drive components * **Robotics & Automation:** Actuator shafts, guide rods, coupling elements ## **7. INTERNATIONAL STANDARDS & EQUIVALENTS** | Standard | Designation | Equivalent Status | Typical Specification for Q&T | | :--- | :--- | :--- | :--- | | **AISI/SAE** | 4140 | Primary Standard | - | | **ASTM** | A29 Grade 4140 | US Standard | Specifies mechanical properties | | **UNS** | G41400 | Unified Numbering | - | | **DIN/EN** | 1.7225 / 42CrMo4 | Direct Equivalent | EN 10083-3 (34CrMo4 class) | | **JIS** | SCM440 | Close Equivalent | G4105 (SCM440) | | **GB** | 42CrMo | Chinese Equivalent | GB/T 3077 | | **ISO** | 42CrMo4 | International | ISO 683-18 | **Note:** The heat treatment specified (845°C oil quench + 540°C temper) produces properties meeting or exceeding requirements for **ASTM A322 Grade 4140** and similar specifications. ## **8. FABRICATION & PROCESSING GUIDELINES** **Machining:** - **Condition:** Difficult in fully hardened state - **Recommended Tools:** Carbide or CBN tooling required - **Cutting Parameters:** Low speeds, moderate feeds, heavy cuts to avoid work hardening - **Coolant:** Flood coolant mandatory for heat dissipation **Grinding:** - Excellent grindability with proper wheels (aluminum oxide or CBN) - Use light passes to avoid thermal damage (tempering or re-hardening) **Welding:** - **NOT RECOMMENDED** in this condition - If welding is unavoidable: Preheat to 260-315°C (500-600°F), use low-hydrogen electrodes, post-heat immediately to 595-650°C (1100-1200°F) and slow cool - Complete re-heat treatment recommended for critical applications **Straightening:** - Only cold straightening with proper support is possible - Limited to minor corrections (<0.5% strain) ## **9. QUALITY ASSURANCE & TESTING** **Standard Certification:** - Mill Test Certificate to EN 10204/3.1 or equivalent - Chemical analysis report - Mechanical properties report (tensile, hardness, impact if specified) **Additional Testing Available:** - Microstructure examination - Grain size determination - Hardenability test (Jominy) - Non-destructive testing (MPI, UT) ## **10. ADVANTAGES & LIMITATIONS** **Advantages:** - Excellent strength-to-weight ratio - Good fatigue resistance and toughness at this strength level - Consistent properties throughout 13mm cross-section - Good wear resistance - Dimensional stability after tempering **Limitations:** - Poor corrosion resistance (requires plating or coating) - Difficult machinability in hardened state - Poor weldability - Limited to sections that can be through-hardened with oil quench ## **11. PACKAGING & HANDLING** **Standard Packaging:** - Bundles of 500-1000 kg, strapped and protected - Individual bars: 3-6 meter standard lengths - Ends painted for identification (typically yellow/black) **Storage:** Keep in dry conditions to prevent rusting **Identification:** Heat number and grade stamped on bar ends --- **Disclaimer:** The properties listed are typical for the specified heat treatment and size. Actual properties may vary based on manufacturing process, chemical composition within specification, and exact heat treatment parameters. Users should conduct their own testing for critical applications. -:- For detailed product information, please contact sales. -: AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] Specification Dimensions Size： Diameter 20-1000 mm Length <6211 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 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] -:- For detailed product information, please contact sales. -:

Packing of AISI 4140 Steel, oil quenched, 13 mm (0.5 in.) round [845°C (1550°F) quench, 540°C (1000°F) temper] -:- 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 2682 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