AISI 9840 Steel Sheet,Plate

AISI 9840 Steel Sheet/Plate, 540°C (1000°F) temper, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: AISI 9840 Steel Sheet/Plate, 540°C (1000°F) temper, 25 mm (1 in.) round Synonyms -:- For detailed product information, please contact sales. -:

AISI 9840 Steel, 540°C (1000°F) temper, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: # **Product Datasheet: AISI 9840 Alloy Steel - Quenched & Tempered Condition** ## **1. Product Overview** **AISI 9840** is a nickel-chromium-molybdenum alloy steel known for its excellent combination of high strength, good toughness, and superior hardenability. This datasheet specifies the material in a **fully heat-treated condition**: oil quenched and tempered at **540°C (1000°F)**, supplied as **25 mm (1 inch) diameter round bars**. This specific tempering temperature produces an optimal balance of strength and ductility, making it suitable for high-stress structural components. The 25 mm round form factor ensures predictable through-hardening characteristics with minimal section sensitivity. ## **2. International Standards & Designations** | System/Authority | Designation | Specification / Standard | | :--- | :--- | :--- | | **UNS** | G98400 | Unified Numbering System | | **AISI / SAE** | 9840 | Standard Alloy Steel Designation | | **ASTM** | A322 | Standard Specification for Steel Bars, Alloy, Standard Grades | | **ASTM** | A29/A29M | General Specification for Steel Bars, Alloy | | **SAE** | J404, J412 | Chemical Composition Standards | | **AMS** | 6324 (similar) | Aerospace Material Specification | | **DIN** | 36CrNiMo4 (similar) | German Standard (approximate equivalent) | | **JIS** | SNCM439 (similar) | Japanese Industrial Standard | ## **3. Chemical Composition (% by Weight)** The nickel-chromium-molybdenum system provides deep hardenability and good core properties in medium-to-large sections. | Element | AISI 9840 Specification Range | Typical % | | :--- | :--- | :--- | | **Carbon (C)** | 0.38 - 0.43 | 0.40 | | **Manganese (Mn)** | 0.70 - 0.90 | 0.80 | | **Phosphorus (P)** | ≤ 0.035 | 0.020 | | **Sulfur (S)** | ≤ 0.040 | 0.025 | | **Silicon (Si)** | 0.20 - 0.35 | 0.25 | | **Nickel (Ni)** | 0.85 - 1.15 | 1.00 | | **Chromium (Cr)** | 0.70 - 0.90 | 0.80 | | **Molybdenum (Mo)** | 0.20 - 0.30 | 0.25 | | **Iron (Fe)** | Balance | Balance | ## **4. Mechanical & Physical Properties (Q&T @ 540°C / 1000°F)** Properties listed are typical for **25 mm (1 inch) diameter round bars**, oil quenched and tempered at 540°C. Larger diameters will exhibit lower core hardness and strength. | Property | Typical Value / Range | Test Standard | Notes | | :--- | :--- | :--- | :--- | | **Condition** | Oil Quenched & Tempered @ 540°C | -- | Ready for use | | **Surface Hardness** | 40 - 44 HRC | ASTM E18 | Measured on bar surface | | **Core Hardness** | 38 - 42 HRC | ASTM E18 | At center of 25mm round | | **Tensile Strength** | 1240 - 1380 MPa (180 - 200 ksi) | ASTM A370 | | | **Yield Strength (0.2%)** | 1100 - 1240 MPa (160 - 180 ksi) | ASTM A370 | | | **Elongation (in 50mm)** | 12% - 16% | ASTM A370 | | | **Reduction of Area** | 40% - 50% | ASTM A370 | | | **Impact Toughness** | 40 - 55 J (30 - 40 ft·lb) | ASTM E23 | Charpy V-notch, room temp | | **Modulus of Elasticity** | 205 GPa (29.7 × 10⁶ psi) | -- | | | **Fatigue Strength** | ~550 - 620 MPa (80 - 90 ksi) | -- | Rotating beam, polished | | **Density** | 7.85 g/cm³ (0.284 lb/in³) | -- | | ## **5. Key Characteristics & Advantages** * **Excellent Strength-Toughness Balance:** The 540°C temper provides an optimal combination for many structural applications. * **Good Through-Hardenability:** Nickel-chromium-molybdenum alloying ensures minimal property gradient in 25mm sections. * **Good Fatigue Resistance:** Suitable for dynamically loaded components. * **Moderate Wear Resistance:** Can be used for sliding/wearing applications with proper lubrication. * **Predictable Machinability (in annealed state):** Typically machined before final heat treatment. ## **6. Primary Applications** This material in the Q&T 540°C condition is ideal for: * **High-Stress Fasteners:** Large bolts, studs, and connecting rods requiring high tensile strength. * **Power Transmission Components:** Gears, shafts, and pinions in automotive and industrial gearboxes. * **Oil & Gas Equipment:** Valve parts, mandrels, and downhole tool components. * **Aerospace Components:** Landing gear parts, actuator components (subject to specific aerospace specifications). * **Heavy Machinery:** Axles, pivot pins, and high-load structural components. * **Tooling Applications:** Jigs, fixtures, and die components requiring high strength with moderate toughness. ## **7. Processing & Fabrication Notes** **Important:** This product is supplied in final heat-treated condition. No further heat treatment is recommended. * **Machining & Grinding:** * Use carbide or ceramic tooling with adequate cooling. * Grinding should use light passes with ample coolant to prevent local overheating. * Stress relieving may be required after heavy machining. * **Welding:** * **Not recommended** in this hardened condition. * If absolutely necessary, use pre-heat (200-300°C) and post-weld tempering. * Consider using annealed material for fabrication, then heat treat. * **Surface Treatments:** * Suitable for plating, phosphating, or nitriding. * Nitriding can significantly improve surface hardness without affecting core properties. ## **8. Heat Treatment History & Assumptions** * **Assumed Austenitizing:** 830-850°C (1525-1560°F) in controlled atmosphere * **Quenching Medium:** Oil * **Tempering:** 540°C (1000°F) for 1-2 hours per inch of thickness * **Microstructure:** Tempered martensite with fine carbide dispersion ## **9. Quality Assurance** Material should be supplied with certification including: * Chemical analysis * Mechanical test results (tensile, hardness) * Heat treatment records * Traceability to original melt --- **Note:** Properties are typical for the specified condition and size. Actual properties may vary based on manufacturer's processing parameters. For critical applications, verification testing on actual material is recommended. -:- For detailed product information, please contact sales. -: AISI 9840 Steel, 540°C (1000°F) temper, 25 mm (1 in.) round Specification Dimensions Size： Diameter 20-1000 mm Length <6399 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 9840 Steel, 540°C (1000°F) temper, 25 mm (1 in.) round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 9840 Steel Sheet,Plate, 540°C (1000°F) temper, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 9840 Steel Sheet,Plate, 540°C (1000°F) temper, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -:

Packing of AISI 9840 Steel Sheet/Plate, 540°C (1000°F) temper, 25 mm (1 in.) round -:- 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 Sheet/Plate 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 2870 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