AISI 8620H Steel, mock carburized, reheated and oil quenched

AISI 8620H Steel, mock carburized, reheated and oil quenched Product Information -:- For detailed product information, please contact sales. -: AISI 8620H Steel, mock carburized, reheated and oil quenched Synonyms -:- For detailed product information, please contact sales. -:

AISI 8620H Steel, mock carburized, reheated and oil quenched Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 8620H Steel, Mock Carburized, Reheated and Oil Quenched** #### **1. Overview** This specification describes AISI 8620H **hardenability-controlled alloy steel** subjected to a specialized **process simulation and property development heat treatment**. The sequence involves: 1. **Mock Carburizing**: The component undergoes the exact **thermal profile** of a carburizing cycle (typically 900-930°C for the required duration) but in a **neutral or inert atmosphere** that prevents carbon enrichment. This simulates the thermal history without altering surface chemistry. 2. **Reheating and Oil Quenching**: Following the mock cycle, the part is **reheated to a lower austenitizing temperature (800-850°C)** and subsequently **oil quenched** to develop the target core microstructure and hardness. 3. **Tempering**: A tempering operation (typically in the range of 150-300°C) is performed to achieve final properties. This is a **critical engineering and validation process**, not a final product state. It is used to precisely evaluate and optimize the **core hardenability, microstructure, and dimensional stability** of 8620H steel components before committing to full-scale carburized production. The "H" designation ensures that the core properties achieved are **highly predictable and consistent**, making this test exceptionally reliable for process qualification. #### **2. International Standards & Designations** This simulation process is referenced in standards governing material testing and heat treatment quality assurance. | Region/System | Standard Designation | Title / Purpose | | :--- | :--- | :--- | | **Material Standard** | **AISI 8620H, SAE J404 & J1268** | Chemical Composition & Hardenability Bands | | **Material Specification** | **ASTM A304** | Alloy Steel Bars Subject to End-Quench Hardenability Requirements | | **Hardenability Testing** | **ASTM A255** | Standard Test Methods for Determining Hardenability of Steel | | **Heat Treatment Process** | **SAE AMS-H-6875** | Heat Treatment of Steel, General Requirements | | **Simulation Practice** | **Common Industry Practice** (e.g., internal Aerospace PSDs, Automotive Specifications) | Often detailed in Process Specification Documents for critical parts. | | **Europe (EN)** | **1.6523H (20NiCrMo2-2H)** | Hardenability-controlled Equivalent | #### **3. Chemical Composition (Uniform Throughout)** Unlike a carburized part, the chemical composition remains homogeneous from surface to core, representing the **core chemistry** of the finished component. **Uniform Core Composition (% by Weight, AISI 8620H):** | Element | Content Range | Metallurgical Role in This Process | | :--- | :--- | :--- | | **Carbon (C)** | 0.17 - 0.23 | Determines the final through-hardened hardness and strength. | | **Manganese (Mn)** | 0.60 - 0.95 | Ensures the H-band hardenability is met, guaranteeing consistent depth of hardening after oil quenching. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; provides solid solution strengthening. | | **Nickel (Ni)** | 0.35 - 0.75 | Provides the core toughness; its effect is fully evaluated in this simulation. | | **Chromium (Cr)** | 0.35 - 0.65 | Contributes to hardenability and tempering resistance. | | **Molybdenum (Mo)** | 0.15 - 0.25 | Inhibits grain growth during the prolonged high-temperature mock cycle; improves hardenability. | | **Key Distinction**: The surface carbon remains at the core level (~0.20%), not enriched. | | | **H-Grade Significance**: The guaranteed hardenability band ensures that the resulting hardness after oil quenching from the reheat temperature will be **highly predictable** for a given section size, validating the material's suitability for the intended component. #### **4. Mechanical & Physical Properties (Final Simulated Condition)** The properties are uniform throughout the cross-section, accurately representing the **core properties** of a potential carburized part. **Typical Properties (After Reheating, Oil Quenching & Tempering):** * **Uniform Hardness:** **35 - 45 HRC** (The exact value is highly predictable based on the H-band and section size). * **Tensile Strength:** **1000 - 1300 MPa** (145 - 189 ksi) * **Yield Strength (0.2% Offset):** **850 - 1150 MPa** (123 - 167 ksi) * **Elongation:** **10% - 15%** * **Reduction of Area:** **45% - 55%** * **Impact Toughness (Charpy V-notch):** **40 - 70 J** (30 - 52 ft-lbf) * **Microstructure:** Tempered martensite (and possibly some lower bainite) throughout. The reheating step refines the prior austenite grain size that may have coarsened during the mock carburizing soak. **Physical Properties:** * Density: 7.85 g/cm³ * Modulus of Elasticity: 205 GPa * Thermal Conductivity: ~45 W/m·K #### **5. Product Applications** This is exclusively a **development, qualification, and troubleshooting process**, not a final service condition. * **Hardenability Verification & Material Qualification:** Confirming that a specific heat of AISI 8620H steel will achieve the required core properties in the actual part geometry after undergoing the full thermal cycle of carburizing. This is often a **mandatory step for certifying new material lots** for aerospace, automotive, or bearing applications. * **Distortion Analysis and Fixture Design:** The single most important application. Measuring the dimensional changes and warpage resulting from the simulated process allows engineers to design effective quenching fixtures and modify processes to minimize distortion in production parts. * **Process Development:** Establishing the optimal reheating temperature, quench agitation, and tempering parameters for a new component design. * **Core Microstructure & Grain Size Studies:** Assessing the risk of austenite grain coarsening during the long high-temperature cycle and the effectiveness of the reheat in refining the grain structure. * **Baseline for Comparison:** Providing a "carburizing thermal history only" baseline to isolate the effects of carbon addition in later experiments. #### **6. Key Characteristics & Advantages of the Mock Carburizing Process** * **Predictive Power for Core Properties:** Allows accurate prediction of final **core hardness, strength, and microstructure** before committing to the irreversible carburizing process. * **Essential for Distortion Control:** Enables the measurement of thermal distortion from the simulated process, which is critical for designing fixtures and processes that yield dimensionally accurate production parts. * **Material and Process Qualification:** A vital tool for qualifying new material suppliers or heats for critical applications, ensuring consistent core performance. * **Cost-Effective Troubleshooting:** Identifies potential issues with hardenability or distortion using low-cost test blanks instead of scrapping expensive, fully carburized components. * **Surface Integrity for Analysis:** The surface remains machinable (not hardened to 60+ HRC), allowing for easy sectioning, metallographic preparation, and detailed microscopic examination. **Conclusion:** **AISI 8620H processed via "Mock Carburized, Reheated and Oil Quenched" is a vital metallurgical simulation and quality assurance tool, not an in-service product.** It represents a **proactive, data-driven engineering approach** to guaranteeing quality, optimizing manufacturing processes, and mitigating risk in the production of high-value, case-hardened components. By decoupling the **thermal effects** from the **chemical effects** of carburizing, this method provides unparalleled insight into the fundamental behavior of the H-grade steel. Its use is a hallmark of advanced manufacturing in sectors like aerospace, premium automotive, and precision bearings, where **first-pass success, dimensional accuracy, and absolute reliability are non-negotiable.** The H-grade certification adds a layer of confidence, ensuring that the results of the mock process are inherently more predictable and representative of full-scale production outcomes. -:- For detailed product information, please contact sales. -: AISI 8620H Steel, mock carburized, reheated and oil quenched Specification Dimensions Size： Diameter 20-1000 mm Length <5740 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 8620H Steel, mock carburized, reheated and oil quenched Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8620H Steel, mock carburized, reheated and oil quenched -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8620H Steel, mock carburized, reheated and oil quenched -:- For detailed product information, please contact sales. -:

Packing of AISI 8620H Steel, mock carburized, reheated and oil quenched -:- 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 2211 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