AISI E4340 Steel Capillary

AISI E4340 Steel Capillary, annealed 810°C (1490°F) Product Information -:- For detailed product information, please contact sales. -: AISI E4340 Steel Capillary, annealed 810°C (1490°F) Synonyms -:- For detailed product information, please contact sales. -:

AISI E4340 Steel, annealed 810°C (1490°F) Product Information -:- For detailed product information, please contact sales. -: ## **Technical Specification: AISI 4340 (UNS G43400) Steel - Subcritical Annealed at 810°C (1490°F)** ### **1. Product Overview** This specification defines **AISI 4340 alloy steel** supplied in a **subcritical annealed condition**, specifically processed by heating to **810°C (1490°F)** followed by controlled slow cooling. Unlike full annealing (performed above the A₃ critical temperature), this treatment is conducted **below the lower critical temperature (Ac₁ ~ 730°C)**. The process is designed to **soften previously hardened or cold-worked material, relieve internal stresses, and produce a uniform microstructure of spheroidized carbides in a ferritic matrix**. This condition provides **optimal machinability and dimensional stability**, serving as an ideal preparatory state for complex machining operations prior to final heat treatment. **Key Characteristics:** * **Superior Machinability:** The soft, spheroidized microstructure minimizes tool wear, allows high material removal rates, and produces excellent surface finishes. * **Effective Stress Relief:** Eliminates residual stresses from prior forging or machining, significantly reducing the risk of distortion during subsequent heat treatment. * **Microstructural Uniformity:** Produces a fine, uniform distribution of carbides, ensuring consistent response during final hardening. * **Processing Flexibility:** Serves as a stable, soft starting condition for components that will later be quenched and tempered, nitrided, or carburized. --- ### **2. Standard Chemical Composition (Weight %)** Composition conforms to standard AISI 4340 specifications. The subcritical anneal softens the material without altering its chemistry. | Element | Content (%) | Role in Subcritical Annealing | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.38 - 0.43 | Forms spheroidized carbides that determine final hardness and machinability. | | **Manganese (Mn)**| 0.60 - 0.80 | Stabilizes carbides; influences spheroidization kinetics. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; provides solid solution strengthening. | | **Nickel (Ni)** | 1.65 - 2.00 | Enhances toughness; does not form carbides but affects overall hardenability. | | **Chromium (Cr)** | 0.70 - 0.90 | Forms stable carbides; promotes fine spheroidization. | | **Molybdenum (Mo)**| 0.20 - 0.30 | Forms very stable carbides; prevents excessive grain growth. | | **Sulfur (S)** | ≤ 0.040 | Residual element (can improve machinability if controlled). | | **Phosphorus (P)** | ≤ 0.035 | Residual element. | --- ### **3. Typical Mechanical & Physical Properties** *Properties are for material subcritically annealed at 810°C with appropriate soak time and controlled furnace cooling.* | Property | Typical Value / Range | Test Standard / Notes | | :--- | :--- | :--- | | **Hardness** | **187 - 217 HB** (Brinell) / **85 - 95 HRB** | ASTM E10/E18 | | **Tensile Strength** | **620 - 720 MPa** (90 - 105 ksi) | ASTM E8 | | **Yield Strength (0.2% Offset)** | **380 - 480 MPa** (55 - 70 ksi) | ASTM E8 | | **Elongation (in 50mm)** | **22% - 28%** | ASTM E8 | | **Reduction of Area** | **50% - 60%** | ASTM E8 | | **Machinability Rating** | **~60%** of 1212 steel | Excellent chip formation, low cutting forces. | | **Microstructure** | **Ferrite matrix with Spheroidized Carbides** | Fine, globular carbides uniformly dispersed. | | **Grain Size** | ASTM 5-7 | Refined, uniform structure. | | **Density** | 7.85 g/cm³ (0.284 lb/in³) | - | --- ### **4. Heat Treatment Parameters** The **810°C Subcritical Anneal** is a precisely controlled process: * **Temperature:** **810°C ± 10°C (1490°F ± 20°F)** * **Soak Time:** 2-4 hours per inch of thickness (depending on prior condition) * **Cooling Rate:** Slow furnace cooling (typically 10-30°C/hour) to below 500°C, then air cool * **Metallurgical Principle:** Heating below Ac₁ allows existing carbides to coalesce into spherical particles (spheroidization) while relieving internal stresses, without forming austenite. **Subsequent Processing:** After machining in this soft condition, components typically undergo: - **Through-hardening:** Re-austenitize at 845-870°C, quench, and temper - **Case hardening:** Directly to carburizing or nitriding cycles --- ### **5. Target Applications** This annealed condition is specified for precision components requiring extensive machining before final hardening. * **Complex Aerospace Components:** Bulkheads, landing gear parts, engine mounts requiring intricate machining * **Precision Gears and Shafts:** High-performance automotive and industrial gear blanks * **Tooling and Dies:** Plastic injection molds, die casting cores, forging dies * **Oil & Gas Equipment:** Complex valve bodies, downhole tool segments * **General High-Strength Components:** Any part requiring significant metal removal before heat treatment --- ### **6. International Standards & Procurement** | Standard | Designation | Status | | :--- | :--- | :--- | | **AISI/SAE** | **4340** (UNS G43400) | Primary reference | | **ASTM** | A29, A331 | Can be ordered as "Annealed" | | **AMS** | AMS 6414 | May specify annealing requirements | | **ISO** | ISO 683-18 | Type **1.6562** | | **EN** | EN 10083-3 | **34CrNiMo6** (1.6582) - "+A" condition | | **JIS** | JIS G4103 | SNCM 439 | | **GB** | GB/T 3077 | 40CrNiMoA | **Procurement Specification:** For guaranteed quality, specify: 1. **Material:** AISI 4340 per applicable standard 2. **Condition:** "Subcritically annealed at 810°C to maximum 217 HB" 3. **Microstructure:** "Spheroidized carbide structure required" 4. **Certification:** Mill test report with chemistry and hardness data **Note:** This is often called a **"process anneal"** or **"spheroidize anneal"** and provides better machinability and subsequent hardening response than simple stress relief. -:- For detailed product information, please contact sales. -: AISI E4340 Steel, annealed 810°C (1490°F) Specification Dimensions Size： Diameter 20-1000 mm Length <6267 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, annealed 810°C (1490°F) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI E4340 Steel Capillary, annealed 810°C (1490°F) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI E4340 Steel Capillary, annealed 810°C (1490°F) -:- For detailed product information, please contact sales. -:

Packing of AISI E4340 Steel Capillary, annealed 810°C (1490°F) -:- 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 Capillary 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 2738 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