AISI E4340 Steel, quenched

AISI E4340 Steel, quenched Product Information -:- For detailed product information, please contact sales. -: AISI E4340 Steel, quenched Synonyms -:- For detailed product information, please contact sales. -:

AISI E4340 Steel, quenched Product Information -:- For detailed product information, please contact sales. -: ## **Product Data Sheet: AISI 4340 (UNS G43400) Alloy Steel - As-Quenched Condition** ### **1. Product Overview** This specification defines AISI 4340 alloy steel in the **as-quenched state**. This is an intermediate, non-serviceable condition where the steel has been austenitized and rapidly cooled (typically in oil) to transform its microstructure entirely into **martensite**. This state represents the **maximum achievable hardness and strength** for the grade, but also exhibits **extremely low toughness and ductility, high internal stresses, and significant brittleness**. Material in this condition is supplied specifically for subsequent **tempering heat treatment**, which is **absolutely required** to develop useful engineering properties by relieving stresses and imparting toughness. **Key Characteristics:** * **Maximum Hardness & Strength:** Achieves the peak hardness potential of the 4340 chemistry. * **Brittle & Unstable:** Not suitable for any structural application in this state due to risk of catastrophic fracture. * **High Internal Stress:** Contains significant thermal and transformation stresses from quenching. * **Processing Intermediate:** Exclusively intended as a precursor to tempering. Final properties are determined by the tempering temperature and time. --- ### **2. Standard Chemical Composition (Weight %)** The composition conforms to standard specifications for AISI 4340 / UNS G43400. | Element | Content (%) | Role in Quench Response | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.38 - 0.43 | **Critical:** Primary determinant of martensite hardness and hardenability. | | **Manganese (Mn)**| 0.60 - 0.80 | Enhances hardenability, ensuring full martensite formation in thicker sections. | | **Silicon (Si)** | 0.15 - 0.35 | Provides solid solution strengthening; aids deoxidation. | | **Nickel (Ni)** | 1.65 - 2.00 | Increases hardenability and improves the toughness of the eventual tempered martensite. | | **Chromium (Cr)** | 0.70 - 0.90 | Boosts hardenability and contributes to secondary hardening during tempering. | | **Molybdenum (Mo)**| 0.20 - 0.30 | Increases hardenability, reduces susceptibility to temper embrittlement. | | **Sulfur (S)** | ≤ 0.040 | Residual element (inclusion former). | | **Phosphorus (P)** | ≤ 0.035 | Residual element (can promote embrittlement). | --- ### **3. Typical Mechanical & Physical Properties (As-Quenched)** *Properties are for a 25mm (1 inch) diameter bar after oil quenching from ~830-850°C (1525-1560°F). This is a high-stress, metastable condition.* | Property | Typical Value | Notes & Cautions | | :--- | :--- | :--- | | **Hardness** | **53 - 58 HRC** / **560 - 650 HB** | Near-maximum for the carbon content. Varies slightly with exact quench severity and section size. | | **Tensile Strength** | ~ **1950 - 2200 MPa (283 - 320 ksi)** (Estimated) | **Extremely high but not measurable** in standard tests due to brittle fracture. | | **Yield Strength** | Not defined | Material fails in a brittle manner before measurable yielding. | | **Elongation / Reduction of Area** | **< 1%** | Essentially zero ductility. | | **Impact Toughness (Charpy V-Notch)** | **< 5 J (≈ 4 ft-lb)** | Extremely brittle. Can shatter upon impact. | | **Internal Stress State** | Very High (Compressive at surface, tensile in core) | A product of thermal gradients during quenching. | | **Machinability** | **Very Poor** | Can only be ground. Any cutting operation risks cracking. | | **Dimensional Stability** | **Poor** | Highly susceptible to distortion or cracking if stressed. | **WARNING:** **Do not put as-quenched components under any tensile, bending, or impact load. They are highly prone to sudden, unpredictable fracture.** --- ### **4. Heat Treatment Context** The as-quenched state is a deliberate step within the full **Quench and Temper (Q&T)** cycle: 1. **Austenitizing:** Heated to **830°C - 870°C (1525°F - 1600°F)** to form a uniform solid solution (austenite). 2. **Quenching (This State):** Rapidly cooled in **agitated oil** (or water for very large sections). This transforms the austenite into hard, brittle **martensite**. 3. **Mandatory Next Step – Tempering:** The material **must be tempered immediately** (or stress-relieved if delay occurs). Reheating to **150°C - 650°C (300°F - 1200°F)** relieves internal stresses, converts martensite to tougher tempered martensite, and develops the final balance of strength and ductility. --- ### **5. Applications & Purpose of Supply** Material is **never used in service in the as-quenched condition**. It is supplied as such for specific manufacturing or heat treatment scenarios: * **Specialized Heat Treaters:** Shops that perform their own tempering may purchase as-quenched parts to control the final tempering process precisely. * **Complex Processing Chains:** For components that require straightening or sizing operations that are easier or only possible on the very hard, as-quenched material **before** it is tempered. This requires extreme caution. * **Controlled Distortion Studies:** In development, to study the effects of quenching alone before tempering. * **Material Stock for Subsequent Processing:** As a raw material state for further thermal or thermochemical processing (e.g., prior to **nitriding** or **carburizing**, where a hardened core is desired before the surface treatment). --- ### **6. International Standards & Procurement Notes** Standards define the base material; the "as-quenched" condition is typically a special requirement. | Standard | Designation | Note on Condition | | :--- | :--- | :--- | | **AISI / SAE (USA)** | **4340** (UNS G43400) | Primary reference. "As-Quenched" is not a standard temper. | | **ASTM (USA)** | A29, A331, A519 | Can be ordered to specific hardness ranges post-quench. | | **AMS (Aerospace)** | AMS 6414 (Bar) | Specifies heat treatment requirements; "as-quenched" would be an interim mill condition. | | **ISO** | ISO 683-18:1996 | Type **1.6562**. | | **EN (Europe)** | EN 10083-3 | **34CrNiMo6** (1.6582) - "+QT" suffix required for final state, not "as-quenched". | | **JIS (Japan)** | JIS G4103 | SNCM 439 | | **GB (China)** | GB/T 3077 | 40CrNiMoA | **Critical Procurement Specification:** When ordering AISI 4340 in the as-quenched condition, the purchase order must explicitly state: 1. **Base Material:** e.g., AISI 4340 per AMS 6414. 2. **Condition:** "Supplied in the as-quenched condition only. Material is untempered." 3. **Quench Parameters (if critical):** e.g., "Oil quenched from 845°C (1550°F)." 4. **Hardness Verification:** Required hardness range after quenching (e.g., 55-58 HRC). 5. **Safety & Handling Warning:** Documentation must include clear warnings about the material's brittleness. **Safety Note:** Parts in the as-quenched state must be handled with extreme care to avoid impact or thermal shock, which can cause them to crack or shatter. -:- For detailed product information, please contact sales. -: AISI E4340 Steel, quenched Specification Dimensions Size： Diameter 20-1000 mm Length <6252 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, quenched Properties -:- For detailed product information, please contact sales. -:

Applications of AISI E4340 Steel, quenched -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI E4340 Steel, quenched -:- For detailed product information, please contact sales. -:

Packing of AISI E4340 Steel, quenched -:- 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 2723 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