AISI E4340 Steel, normalized

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

AISI E4340 Steel, normalized Product Information -:- For detailed product information, please contact sales. -: ## **Product Data Sheet: AISI 4340 (UNS G43400) Steel - Normalized Condition** ### **1. Product Overview** AISI 4340 steel in the **normalized condition** is a versatile, medium-carbon, low-alloy steel belonging to the nickel-chromium-molybdenum (Ni-Cr-Mo) family. The normalization heat treatment involves austenitizing followed by air cooling, resulting in a refined, uniform microstructure of fine pearlite with ferrite. This process enhances the steel’s **toughness, grain structure uniformity, and dimensional stability** compared to the as-rolled or annealed conditions, providing an excellent balance of strength and machinability. It serves as a superior starting condition for further machining and final heat treatment (quenching and tempering) or as a service condition for certain non-critical applications. **Key Characteristics:** * **Refined & Uniform Microstructure:** Eliminates coarse grain structures from prior hot-working, improving mechanical property consistency. * **Enhanced Toughness:** Offers better impact resistance than the annealed condition at a slightly higher strength level. * **Good Machinability:** Although harder than annealed material, it remains readily machinable with proper tooling. * **Ideal Pre-Conditioning:** Normalization is often specified prior to final hardening to ensure predictable and uniform response to quenching, minimizing distortion risks. --- ### **2. Standard Chemical Composition (Weight %)** The composition conforms to standard specifications for AISI 4340 / UNS G43400. | Element | Content (%) | Primary Function | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.38 - 0.43 | Core hardness & strength | | **Manganese (Mn)**| 0.60 - 0.80 | Hardenability, deoxidizer | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer, strength | | **Nickel (Ni)** | 1.65 - 2.00 | Toughness, hardenability | | **Chromium (Cr)** | 0.70 - 0.90 | Hardenability, wear resistance | | **Molybdenum (Mo)**| 0.20 - 0.30 | Hardenability, temper resistance | | **Sulfur (S)** | ≤ 0.040 (Typ.) | Residual (lower for better toughness) | | **Phosphorus (P)** | ≤ 0.035 (Typ.) | Residual (lower for better toughness) | --- ### **3. Typical Mechanical & Physical Properties (Normalized Condition)** *Properties are for material normalized from ~ 870°C (1600°F) and air-cooled. Results are typical for medium sections.* | Property | Typical Value | Test Standard / Note | | :--- | :--- | :--- | | **Tensile Strength** | 750 - 950 MPa (109 - 138 ksi) | ASTM A370 | | **Yield Strength (0.2% Offset)** | 470 - 620 MPa (68 - 90 ksi) | ASTM A370 | | **Elongation (in 50mm / 2")** | 18% - 22% | ASTM A370 | | **Reduction of Area** | 45% - 55% | ASTM A370 | | **Hardness** | 220 - 280 Brinell (HB) | ASTM E10 | | **Charpy Impact (V-Notch)** | 40 - 60 J (30 - 44 ft-lb) at 21°C | ASTM A370 | | **Modulus of Elasticity** | 205 GPa (29.7 x 10⁶ psi) | - | | **Poisson's Ratio** | 0.29 | - | | **Density** | 7.85 g/cm³ (0.284 lb/in³) | - | | **Thermal Conductivity** | ~44.5 W/m·K (at 100°C) | - | | **Specific Heat** | ~460 J/kg·K | - | --- ### **4. Heat Treatment Information** * **Normalizing Process:** Heat uniformly to **870°C - 925°C (1600°F - 1700°F)**, hold for sufficient time (approx. 1 hour per inch of thickness), then cool in still air. * **Purpose:** Refines grain size, homogenizes microstructure, relieves internal stresses, and improves toughness for subsequent operations. * **Subsequent Treatment:** Normalized 4340 is almost always subjected to final **Quenching & Tempering (Q&T)**. It is austenitized, rapidly quenched in oil, and tempered at a selected temperature (e.g., 425°C - 650°C / 800°F - 1200°F) to achieve the desired high-strength/toughness combination (e.g., tensile strength up to 1900 MPa / 275 ksi). --- ### **5. Primary Applications** Normalized AISI 4340 is specified for components requiring a reliable, uniform starting structure for machining and final heat treatment, or for applications where its as-normalized properties provide sufficient performance. * **Heavy-Duty Gearing & Pinions:** Normalization ensures uniform response to case hardening or through-hardening. * **Large Forgings & Axles:** For automotive, truck, and off-highway equipment, normalization refines the grain structure of large cross-sections. * **Machine Tool Components:** Spindles, shafts, and beds where stability and uniformity are critical before final hardening. * **Oilfield Components:** Large-diameter drill collars, tool joints, and mandrels. * **Aerospace Structural Components:** Parts that will be machined and then heat-treated to high strength levels. * **General Engineering Components:** Bolts, studs, and critical fasteners (prior to Q&T). --- ### **6. International Standard Cross-Reference** AISI 4340 is a globally recognized grade with close equivalents in major standards systems. | Standard | Designation | Status / Note | | :--- | :--- | :--- | | **AISI / SAE (USA)** | **4340** (UNS G43400) | **Primary Reference** | | **ASTM (USA)** | A29 (Bar), A331 (Bar), A519 (Tube) | Common product standards | | **AMS (Aerospace)** | AMS 6359 (Sheet/Strip), AMS 6414 (Bar) | Aerospace material specs | | **ISO** | ISO 683-18:1996 | Type **1.6562** | | **EN (Europe)** | EN 10083-3 | **34CrNiMo6** (1.6582) - Closest equivalent | | **JIS (Japan)** | JIS G4103 | **SNCM 439** | | **GB (China)** | GB/T 3077 | **40CrNiMoA** | | **DIN (Germany)** | DIN 17200 | **34CrNiMo6** | **Note:** Direct equivalence is not always guaranteed. Chemical ranges, especially for residual elements, and mandatory mechanical properties can differ. **AISI 4340 / UNS G43400** should be the specified requirement for procurement. -:- For detailed product information, please contact sales. -: AISI E4340 Steel, normalized Specification Dimensions Size： Diameter 20-1000 mm Length <6246 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, normalized Properties -:- For detailed product information, please contact sales. -:

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

Packing of AISI E4340 Steel, normalized -:- 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 2717 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