AISI 4718 Steel Wire

AISI 4718 Steel Wire, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round Product Information -:- For detailed product information, please contact sales. -: AISI 4718 Steel Wire, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round Synonyms -:- For detailed product information, please contact sales. -:

AISI 4718 Steel, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round Product Information -:- For detailed product information, please contact sales. -: # Technical Data Sheet: AISI 4718 Steel – Pseudocarburized, Reheated & Quenched, Tempered Condition ## 1. Product Overview **AISI 4718** steel processed through **pseudocarburizing, reheating to 765°C (1700°F), oil quenching, and low-temperature tempering at 150°C (300°F)** represents a specialized heat treatment methodology for simulating the **core properties** of carburized components. This 25 mm (1 inch) round product has undergone a complete thermal cycle that mimics the time-temperature profile of carburizing without actually introducing additional carbon. The subsequent reheat, quench, and temper develop a fine-grained, high-strength microstructure that accurately represents the core of a fully carburized part. This treatment is essential for evaluating machinability, dimensional stability, and core mechanical properties before committing to actual carburizing, particularly for prototyping and quality assurance of high-value components. ## 2. Material Specifications & Standards * **UNS Designation:** G47180 * **AISI/SAE:** 4718 * **Primary Material Standards:** * **ASTM A534** - Standard Specification for Carburizing Steels for Anti-Friction Bearings * **SAE J404** - Chemical Compositions of SAE Alloy Steels * **Heat Treatment Reference Standards:** * **AMS 2759/7** - Carburizing and Carbonitriding * **ISO 683-11** - Through-hardening and case-hardening steels * **International Equivalents:** * **EN/DIN:** 18NiCrMo14-6 (1.6562) * **JIS:** SNCM418 * **GB:** 18CrNiMo7-6 ## 3. Chemical Composition (SAE J404/AISI Standard) The composition of AISI 4718 is designed to provide excellent core toughness and hardenability for carburized applications. | Element | Content Range (%) | Metallurgical Function | |---------|-------------------|------------------------| | Carbon (C) | 0.16–0.21 | Provides core hardenability and strength while maintaining good toughness | | Manganese (Mn) | 0.70–0.90 | Enhances hardenability and strength | | Silicon (Si) | 0.15–0.35 | Deoxidizer, solid solution strengthening | | Nickel (Ni) | 0.90–1.20 | Significantly improves core toughness and hardenability | | Chromium (Cr) | 0.35–0.55 | Increases hardenability, promotes fine microstructure | | Molybdenum (Mo) | 0.08–0.15 | Refines grain structure, improves hardenability | | Phosphorus (P) | ≤0.035 | Residual element | | Sulfur (S) | ≤0.040 | Residual element | ## 4. Heat Treatment Process & Metallurgical Rationale ### 4.1 Processing Sequence: 1. **Pseudocarburizing:** * **Temperature:** 925–945°C (1695–1735°F) – typical carburizing temperature range * **Time:** Equivalent to intended case depth cycle (typically 4–8 hours for 25 mm round) * **Atmosphere:** Neutral (non-carburizing) atmosphere, typically endothermic gas * **Purpose:** Subjects the material to the same thermal exposure as actual carburizing without carbon enrichment, simulating grain growth and thermal history 2. **Reheating & Austenitizing:** * **Temperature:** 765°C (1410°F) – **significantly lower than standard hardening temperature** * **Rationale:** This temperature is: * Below the Ac₃ point for this steel (≈780–800°C) * In the intercritical range (α+γ phase field) * Designed to produce a fine, refined austenite grain size from the previously pseudocarburized structure 3. **Oil Quenching:** * **Quenchant:** Fast oil, 50–70°C (120–160°F) * **Result:** Produces a mixture of low-carbon martensite and possibly some bainite/ferrite * **Microstructure:** Ultra-fine, multiphase structure with excellent toughness 4. **Tempering:** * **Temperature:** 150°C (300°F) * **Time:** 2–3 hours * **Purpose:** Relieves quenching stresses while maintaining high strength ## 5. Mechanical & Physical Properties (25 mm Round) ### 5.1 As-Treated Properties: | Property | Typical Value | Test Standard | Notes | |----------|---------------|---------------|-------| | **Hardness** | 40–45 HRC | ASTM E18 | Consistent through cross-section | | **Tensile Strength** | 1300–1450 MPa (188–210 ksi) | ASTM E8 | Higher than conventional hardening due to fine microstructure | | **Yield Strength (0.2%)** | 1100–1250 MPa (160–181 ksi) | ASTM E8 | Excellent yield-to-tensile ratio | | **Elongation** | 10–14% | ASTM E8 | Good for this strength level | | **Reduction of Area** | 45–55% | ASTM E8 | Indicates good toughness | | **Impact Toughness (Charpy V)** | 35–50 J (26–37 ft-lb) @ RT | ASTM E23 | Excellent for 40+ HRC hardness | | **Grain Size** | ASTM 10–12 | ASTM E112 | Ultra-fine due to intercritical austenitizing | ### 5.2 Microstructural Characteristics: * **Primary Phase:** Fine tempered martensite * **Secondary Phases:** Possible small amounts of bainite and ferrite * **Grain Structure:** Extremely refined due to intercritical heat treatment * **Carbides:** Fine, uniformly dispersed alloy carbides ## 6. Key Performance Characteristics ### 6.1 Advantages of This Specific Treatment: 1. **Accurate Core Simulation:** Provides exact core properties of carburized parts for design verification 2. **Ultra-Fine Microstructure:** Intercritical hardening produces grain refinement beyond conventional quenching 3. **Excellent Toughness/Strength Balance:** Unique combination of high strength (40–45 HRC) with good impact resistance 4. **Predictable Machining Response:** Allows evaluation of final machining operations on "as-carburized" core material 5. **Dimensional Stability Study:** Enables assessment of distortion behavior before actual carburizing ### 6.2 Unique Metallurgical Aspects: * **Intercritical Processing:** The 765°C reheat temperature creates a dual-phase structure that refines during subsequent quenching * **Pseudocarburizing Effect:** Simulates grain growth and thermal history of actual carburizing without carbon gradient * **Temper Response:** Low-temperature temper maintains high hardness while relieving stresses ## 7. Applications & Use Cases ### 7.1 Primary Applications: * **Prototype Development:** Testing core properties before committing to production carburizing * **Machinability Studies:** Evaluating cutting tools and parameters on "final condition" material * **Dimensional Analysis:** Studying distortion and growth during simulated carburizing cycles * **Quality Assurance:** Creating material standards for core property verification * **Research & Development:** Investigating core microstructure-property relationships ### 7.2 Industry Applications: * **Aerospace:** Prototype gear and bearing cores * **Automotive:** Transmission component development * **Bearing Manufacturing:** Core property qualification for anti-friction bearings * **Heavy Equipment:** Development of large carburized components ## 8. Manufacturing Considerations ### 8.1 Material Preparation: * **Initial Condition:** Typically supplied annealed (170–210 HB) for machining * **Machining:** Performed before pseudocarburizing treatment * **Stress Relieving:** Optional after heavy machining ### 8.2 Post-Treatment Processing: * **Final Machining:** Limited – primarily grinding operations * **Inspection:** Complete dimensional and NDT evaluation * **Testing:** Mechanical property verification ## 9. Comparative Analysis | Property | Conventional Q&T (870°C) | This Treatment (765°C) | Advantage | |----------|-------------------------|------------------------|-----------| | Hardness | 38–42 HRC | 40–45 HRC | Higher strength | | Toughness | 25–35 J | 35–50 J | Better impact resistance | | Grain Size | ASTM 8–9 | ASTM 10–12 | Finer structure | | Distortion | Moderate | Predictable (simulated carb) | Better simulation | ## 10. Quality Control Requirements ### 10.1 Mandatory Testing: * **Chemical Analysis:** Verification of AISI 4718 composition * **Hardness Survey:** Multiple points across diameter * **Microstructure:** Grain size and phase identification * **Mechanical Testing:** Tensile and impact properties ### 10.2 Documentation: * **Heat Treatment Records:** Complete cycle documentation * **Material Traceability:** Heat number and processing history * **Test Reports:** Certified mechanical properties ## 11. Technical Limitations 1. **Section Size Sensitivity:** Properties are specific to 25 mm round; larger sections may show variation 2. **Surface Condition:** No carburized case exists – surface is same as core 3. **Temperature Sensitivity:** The 765°C process requires precise temperature control 4. **Application Limitation:** Not for final parts – for development and testing only ## 12. Storage & Handling * **Condition:** Supplied in final heat treated condition * **Protection:** VCI packaging or protective coating to prevent corrosion * **Identification:** Clearly marked as "PSEUDOCARBURIZED - NOT FOR FINAL USE" * **Shelf Life:** Indefinite with proper corrosion protection --- ## 13. Special Notes **Important:** This product is intended for **engineering development, testing, and qualification purposes only**. It represents the core condition of what would become a carburized component but lacks the hardened case. It should not be used in actual service applications where case hardening is required. **Typical Next Steps:** After evaluation of this pseudocarburized material, the actual production components would undergo: 1. Final machining to specified dimensions 2. Actual carburizing cycle 3. Final quenching and tempering 4. Finish grinding and inspection *This technical data sheet provides representative values for this specialized heat treatment condition. Actual properties may vary based on specific processing parameters and should be verified through testing for critical applications.* -:- For detailed product information, please contact sales. -: AISI 4718 Steel, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round Specification Dimensions Size： Diameter 20-1000 mm Length <5658 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 4718 Steel, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4718 Steel Wire, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4718 Steel Wire, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 25 mm round -:- For detailed product information, please contact sales. -:

Packing of AISI 4718 Steel Wire, pseudocarburized, reheated to 765°C (1700°F) and oil quenched, 150°C (300°F) temper, 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 Wire 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 2129 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