AISI 4620 Steel Capillary

AISI 4620 Steel Capillary, annealed, 25 mm round Product Information -:- For detailed product information, please contact sales. -: AISI 4620 Steel Capillary, annealed, 25 mm round Synonyms -:- For detailed product information, please contact sales. -:

AISI 4620 Steel, annealed, 25 mm round Product Information -:- For detailed product information, please contact sales. -: # **Technical Specification: AISI 4620 Steel, Annealed Condition, 25 mm Round Bar** ## **1. PRODUCT OVERVIEW** AISI 4620 steel supplied as **25 mm (1.0 inch) diameter round bars in the annealed condition** represents a premium low-carbon nickel-molybdenum alloy steel in its softest and most machinable state. This material is specifically engineered as an **ideal pre-hardening stock** for components destined for case hardening processes such as carburizing or carbonitriding. The annealed condition provides a **coarse ferrite-pearlite microstructure** with minimal residual stresses, offering optimal ductility, superior machinability, and excellent dimensional stability during subsequent manufacturing operations. The 25 mm diameter is a versatile industrial standard, suitable for machining into a wide range of medium-sized, high-performance parts requiring a tough core beneath a wear-resistant case. ## **2. PRODUCT SPECIFICATIONS & STANDARDS** | **Parameter** | **Specification** | **Governing Standards** | |---------------|-------------------|-------------------------| | **Material Designation** | AISI 4620 / SAE 4620 | SAE J404, SAE J412 | | **UNS Number** | G46200 | ASTM A29 | | **International Equivalents** | DIN 1.6523 (similar), 20NiCrMo2-2 | ISO 683-11:2016 | | **Product Form** | Hot-rolled or cold-finished round bar | ASTM A29/A29M | | **Diameter** | 25.0 mm ± 0.3 mm (1.0 in. ± 0.012 in.) | Commercial Tolerance | | **Condition** | Annealed (Full Anneal or Subcritical Anneal) | — | | **Typical Hardness** | 149-179 HB (85-92 HRB) | ASTM E10/E18 | | **Straightness** | ≤ 1.5 mm per 300 mm (0.06 in./ft) | Standard commercial | | **Surface Finish (as-supplied)** | Hot-rolled & descaled or cold-drawn | Optional turned/polished available | ## **3. CHEMICAL COMPOSITION** | **Element** | **Minimum (%)** | **Maximum (%)** | **Typical (%)** | **Function in Annealed State** | |-------------|-----------------|-----------------|-----------------|-------------------------------| | **Carbon (C)** | 0.17 | 0.22 | 0.19 | Provides base strength; low enough for excellent machinability, sufficient for subsequent case hardening. | | **Manganese (Mn)** | 0.45 | 0.65 | 0.55 | Aids deoxidation; contributes to future hardenability. | | **Phosphorus (P)** | — | 0.035 | 0.015 | Residual element (controlled). | | **Sulfur (S)** | — | 0.040 | 0.025 | Promotes chip breaking, improves machinability in annealed state. | | **Silicon (Si)** | 0.15 | 0.35 | 0.25 | Deoxidizer; provides slight solid solution strengthening. | | **Nickel (Ni)** | 1.65 | 2.00 | 1.80 | **Key element:** Provides inherent toughness to the core even in this soft state; ensures exceptional core properties after carburizing. | | **Molybdenum (Mo)** | 0.20 | 0.30 | 0.25 | Prevents grain growth during future high-temperature carburizing; improves hardenability. | | **Iron (Fe)** | Balance | Balance | Balance | Matrix. | **Key Characteristics for 25 mm Annealed Rounds:** * **Carbon Equivalent (CE):** ~0.40-0.45 – Indicates good weldability in this condition. * **Machinability Index:** Excellent (~70-75% of 1212 steel free-machining standard). * **Uniformity:** The 25 mm section ensures consistent cooling during annealing, resulting in uniform microstructure and properties from surface to center. ## **4. ANNEALING PROCESS & MICROSTRUCTURE** ### **4.1 Typical Annealing Cycle** The material is heated to a temperature above the Ac₃ line (typically ~850-900°C / 1560-1650°F) and slowly furnace-cooled to produce maximum softness. **Resultant Microstructure (25 mm Section):** * **Matrix:** Coarse, equiaxed ferrite grains. * **Secondary Phase:** Spheroidized or lamellar pearlite/carbides uniformly distributed. * **Grain Size:** ASTM 5-7 (coarse, ideal for machining). * **Key Feature:** This structure is stress-free and provides the lowest possible hardness, enabling aggressive machining with long tool life. ## **5. MECHANICAL PROPERTIES (ANNEALED CONDITION)** | **Property** | **Value Range** | **Test Standard** | **Notes for 25 mm Round** | |--------------|-----------------|-------------------|---------------------------| | **Hardness** | 149-179 HB (85-92 HRB) | ASTM E10/E18 | Very consistent through cross-section. | | **Ultimate Tensile Strength** | 490-590 MPa (71-86 ksi) | ASTM E8/E8M | Longitudinal direction. | | **Yield Strength (0.2% offset)** | 275-380 MPa (40-55 ksi) | ASTM E8/E8M | | | **Elongation (in 50 mm)** | 28-35% | ASTM E8/E8M | Excellent ductility. | | **Reduction of Area** | 60-70% | ASTM E8/E8M | | | **Modulus of Elasticity** | 200-205 GPa (29,000-29,700 ksi) | ASTM E111 | | | **Charpy V-Notch Impact (20°C)** | 60-90 J (44-66 ft·lb) | ASTM E23 | **Exceptionally high** due to Ni content and soft structure. | | **Machinability Rating** | 70-75% (vs. 1212 steel) | Industry Standard | Excellent chip formation, low cutting forces. | ## **6. PHYSICAL PROPERTIES** | **Property** | **Value** | **Unit** | |--------------|-----------|----------| | Density | 7.85 | g/cm³ | | Thermal Conductivity (20°C) | 46.0 | W/m·K | | Specific Heat (20°C) | 475 | J/kg·K | | Mean CTE (20-100°C) | 12.3 × 10⁻⁶ | /K | | Electrical Resistivity (20°C) | 0.21 | μΩ·m | | Magnetic Properties | Ferromagnetic | — | ## **7. APPLICATIONS** AISI 4620 annealed 25 mm round is **not a final-use product** but a **primary manufacturing stock**. It is selected to be machined into near-net-shape components which are then case-hardened. ### **7.1 Target Component Families** | **Industry** | **Typical Components Machined from This Stock** | |--------------|-------------------------------------------------| | **Automotive** | Transmission gears, synchro hubs, differential side gears, shift forks, camshafts, high-strength fasteners. | | **Aerospace** | Actuator gears, linkage components, non-critical structural pins, fastener blanks. | | **Heavy Machinery** | Sprockets, pinions, hydraulic pump gears, lever arms, bushings. | | **General Engineering** | Custom shafts, rollers, studs, tooling blanks, prototypes. | ### **7.2 Why Use Annealed 4620 in 25 mm Rounds?** 1. **Superior Machinability:** Maximizes tool life, allows higher cutting speeds, and produces excellent surface finishes, reducing finishing costs. 2. **Dimensional Stability:** The stress-relieved, annealed state minimizes distortion during and after machining, holding tighter tolerances. 3. **Formability:** Can be cold-formed (bending, heading) if required before hardening. 4. **Predictable Hardening Response:** Provides a uniform, known starting condition for the carburizing process, leading to consistent case depth and core properties. ## **8. PROCESSING CHARACTERISTICS** ### **8.1 Machinability (Primary Advantage)** | **Operation** | **Recommended Parameters** | **Tooling Suggestions** | |---------------|----------------------------|-------------------------| | **Turning** | Vc = 160-200 m/min, f = 0.25-0.4 mm/rev | Uncoated or TiN-coated carbide. | | **Drilling** | Vc = 30-40 m/min, f = 0.2-0.3 mm/rev | HSS-Co or carbide drills. | | **Milling** | Vc = 130-170 m/min, fz = 0.15-0.25 mm/tooth | Carbide end mills. | | **Tapping** | 70-80% of drilling speed | TiN-coated HSS taps. | ### **8.2 Subsequent Heat Treatment (Typical)** * **Process:** Gas Carburizing at 900-925°C → Oil Quench → Low-Temperature Temper (150-200°C). * **Expected Final Properties:** * **Case Hardness:** 58-63 HRC. * **Effective Case Depth:** Adjustable (e.g., 0.5-1.5 mm). * **Core Hardness:** 35-42 HRC (tough, strong core due to Ni-Mo). * **Pre-Machining Note:** All complex machining, drilling, and tapping **must** be completed in this annealed state. ### **8.3 Weldability (Annealed Condition)** * **Rating:** Good (with precautions). * **Procedure:** Preheating (100-150°C) recommended for sections >12 mm. Use low-hydrogen electrodes (AWS E8018-C3). Post-weld heat treatment is advisable, especially before final carburizing. ## **9. INTERNATIONAL STANDARDS & EQUIVALENTS** | **Standard** | **Designation / Approach** | **Notes** | |--------------|----------------------------|-----------| | **SAE (USA)** | 4620 | Base standard. | | **ASTM (USA)** | A29/A29M (Grade 4620) | Standard specification for steel bars. Condition "Annealed" must be specified. | | **DIN (Germany)** | 1.6523 / 20NiCrMo2-2 | Similar Ni-Cr-Mo steel. A closer chemical match might be a modified 1.6523. | | **ISO** | ISO 683-11:2016 | Case-hardening steels. | | **JIS (Japan)** | SNCM220 | Common equivalent (contains Cr, similar performance). | ## **10. QUALITY ASSURANCE** Standard supply includes: * **Mill Test Certificate:** Confirming chemical composition meets AISI 4620. * **Hardness Report:** Typically a Brinell test. * **Dimensional Report:** Certifying diameter and straightness. For critical applications, additional tests can be specified: * **Microstructure Examination:** To verify annealed structure. * **Ultrasonic Testing:** For internal soundness. * **Charpy Impact Test:** To verify inherent toughness. ## **11. DESIGN & PURCHASING GUIDELINES** * **Stock Allowance:** Remember to include sufficient stock for final grinding after carburizing (typically 0.2-0.3 mm per side). * **Ordering Specification:** Clearly state: **"AISI 4620, Annealed, 25 mm Round Bar, ASTM A29"**. * **Alternative Conditions:** If less machinability but higher strength is needed before final hardening, consider **"Normalized"** condition (~187-229 HB). ## **12. SUMMARY** **AISI 4620 in 25 mm annealed round bar is the optimal starting point for manufacturing high-performance, case-hardened components.** It delivers unparalleled machinability and dimensional stability for complex part geometries, ensuring cost-effective production. Its nickel-molybdenum chemistry guarantees that, once carburized, the final part will possess a hard, wear-resistant surface backed by an exceptionally tough and strong core, capable of withstanding high dynamic loads and impact. This material is a proven choice for demanding applications in automotive, aerospace, and heavy industry supply chains. --- **Disclaimer:** The properties listed are typical for commercially annealed material. Actual values can vary based on the specific annealing cycle and mill practices. For design-critical applications, prototype testing is recommended. -:- For detailed product information, please contact sales. -: AISI 4620 Steel, annealed, 25 mm round Specification Dimensions Size： Diameter 20-1000 mm Length <5638 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 4620 Steel, annealed, 25 mm round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4620 Steel Capillary, annealed, 25 mm round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4620 Steel Capillary, annealed, 25 mm round -:- For detailed product information, please contact sales. -:

Packing of AISI 4620 Steel Capillary, annealed, 25 mm 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 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 2109 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