AISI 8640 Steel, cold drawn

AISI 8640 Steel, cold drawn, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: AISI 8640 Steel, cold drawn, 25 mm (1 in.) round Synonyms -:- For detailed product information, please contact sales. -:

AISI 8640 Steel, cold drawn, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: ### **Product Data Sheet: AISI 8640 Alloy Steel – Cold Drawn Condition** #### **1. Product Identification & Overview** **Designation:** AISI 8640 / UNS G86400 **Condition:** Cold Drawn (CD), Stress Relieved (SR) **Form & Size:** Round Bar, 25 mm (1 inch) Diameter **Classification:** Nickel-Chromium-Molybdenum Low-Alloy Steel **Key Characteristics:** This product refers to AISI 8640 alloy steel bar that has been processed through cold drawing at room temperature after initial hot rolling and annealing. This cold working operation significantly improves the material's surface finish, dimensional accuracy, and straightness, while also increasing its yield and tensile strength through strain hardening. It is typically supplied in a **"cold drawn, stress relieved"** condition to optimize machinability and dimensional stability. This form is ideal for the high-volume production of precision parts that require excellent surface quality and consistent mechanical properties without subsequent heat treatment by the end-user. #### **2. International Standard Compliance** This product is manufactured to meet the dimensional tolerances, chemical, and standard mechanical property requirements of the following international standards: * **ASTM:** A311 / A311M (Standard Specification for Cold-Drawn, Stress-Relieved Carbon and Alloy Steel Bars Subject to Mechanical Property Requirements) * **ASTM:** A29 / A29M (Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought and Cold-Finished) * **SAE / AISI:** SAE J404, J412 (Chemical Composition) - Designation 8640 * **UNS:** G86400 * **ISO:** 683-11 (Heat-treatable steels) - Note: Cold-drawn condition specifics are often covered by separate dimensional and delivery condition standards. #### **3. Chemical Composition (Weight %)** The composition is identical to standard AISI 8640. The cold drawing process alters the mechanical properties, not the chemistry. | Element | Standard Range | Typical Value | |--------------|----------------|---------------| | Carbon (C) | 0.38 - 0.43 | 0.40 | | Manganese (Mn)| 0.75 - 1.00 | 0.85 | | Silicon (Si) | 0.15 - 0.30 | 0.25 | | Nickel (Ni) | 0.40 - 0.70 | 0.55 | | Chromium (Cr)| 0.40 - 0.60 | 0.50 | | Molybdenum (Mo)| 0.15 - 0.25 | 0.20 | | Phosphorus (P) max | 0.035 | 0.020 | | Sulfur (S) max | 0.040 | 0.025 | | **Iron (Fe)** | **Balance** | **Balance** | #### **4. Physical & Mechanical Properties (As Cold Drawn & Stress Relieved)** *Properties are typical for a 25 mm (1 inch) diameter cold drawn, stress-relieved bar. The cold work significantly increases strength over the hot-rolled annealed condition.* | Property | Typical Value | Metric Units | Imperial Units | | ----------------------------------- | ----------------------------- | -------------------- | -------------------- | | **Tensile Strength** | 700 - 860 | MPa | 102 - 125 ksi | | **Yield Strength (0.2% Offset)** | **515 - 620** (Minimum) | MPa | **75 - 90 ksi** (Min)| | **Elongation at Break** | 12 - 18 | % in 50 mm | % in 2 in | | **Reduction of Area** | 45 - 55 | % | % | | **Hardness** | 197 - 241 | HB | 197 - 241 HB | | | ~93 - 100 | HRB | | | **Machinability Rating** | ~65% (vs. 100% for B1112) | - | - | | **Modulus of Elasticity** | ~205 | GPa | 29.7 x 10⁶ psi | | **Density** | 7.85 | g/cm³ | 0.284 lb/in³ | | **Surface Finish (Ra)** | 3.2 - 1.6 μm | μm | 125 - 63 μin | **Key Processing & Performance Notes:** * **Condition:** Supplied as **Cold Drawn, Stress Relieved (CD-SR)**. The stress relief treatment (heating to ~595-650°C / 1100-1200°F) reduces internal stresses from drawing, improving machinability and dimensional stability during subsequent cutting. * **Strength:** The cold drawing process introduces significant strain hardening, resulting in a higher yield strength and better straightness compared to hot-rolled bars. * **Dimensional Accuracy:** Cold drawing provides tighter diameter tolerances (e.g., ±0.08 mm for 25mm dia. per ASTM A311) and superior surface finish. * **Subsequent Heat Treatment:** This material is **NOT in a heat-treated (Q&T) state**. It is designed to be **machined first** and then **heat treated (quenched and tempered)** to achieve its final high-strength properties, if required by the application. The uniform, fine-grained structure of cold-drawn material responds very predictably to final heat treatment. * **Weldability:** Fair. Welding is generally not recommended in the cold-worked condition as it can create a brittle heat-affected zone. If welding is necessary, the part should be fully annealed first or heat treated after welding. #### **5. Detailed Product Applications** Cold drawn AISI 8640 rounds are the preferred starting material for manufacturers who require consistent, high-quality bar stock for machining parts that will later be heat treated. **Primary Applications (as a machining blank):** * **Precision Shafting:** Axles, spindles, piston rods, and linear motion shafts that require tight tolerances and a smooth surface finish before final hardening. * **Gear and Sprocket Blanks:** Ideal stock for cutting gears, pinions, and sprockets that will later be carburized or through-hardened. * **Hydraulic and Pneumatic Components:** Cylinder rods, valve bodies, and pump parts. * **Fastener Manufacturing:** High-strength bolts, studs, and cap screws (typically machined and then heat treated). * **Automotive Components:** Steering components, transmission shafts, and other critical parts where dimensional consistency in the "soft" state is crucial for automated machining. * **General Machined Parts:** Any application requiring a superior surface finish and dimensional accuracy in the "as-supplied" state for efficient CNC machining. #### **6. Processing Guidelines** * **Machining (Primary Operation):** This material is supplied specifically for machining. It offers good chip formation and predictable tool wear. Using sharp tools and adequate coolant is recommended. * **Heat Treatment (After Machining):** To achieve final service properties, parts must be austenitized (e.g., 845°C / 1550°F), quenched (oil), and tempered to the desired hardness/strength level (e.g., 540°C / 1000°F for strength, 650°C / 1200°F for toughness). * **Straightness:** Cold drawn bars exhibit excellent straightness, minimizing the need for straightening prior to setup in CNC lathes or screw machines. * **Storage & Handling:** Store in a dry environment to prevent surface rust. The smooth surface is more prone to visible corrosion staining than a hot-rolled scale surface. --- **Disclaimer:** The information provided is for reference purposes. Actual properties, especially yield and tensile strength, can vary based on the specific amount of cold work (reduction in area during drawing) and the stress-relief parameters. Users should conduct their own testing for critical applications. Always consult relevant material standards and safety data sheets. -:- For detailed product information, please contact sales. -: AISI 8640 Steel, cold drawn, 25 mm (1 in.) round Specification Dimensions Size： Diameter 20-1000 mm Length <6346 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 8640 Steel, cold drawn, 25 mm (1 in.) round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8640 Steel, cold drawn, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8640 Steel, cold drawn, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -:

Packing of AISI 8640 Steel, cold drawn, 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 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 2817 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