AISI 8625H Steel Seamless tube

AISI 8625H Steel Seamless tube Product Information -:- For detailed product information, please contact sales. -: AISI 8625H Steel Seamless tube Synonyms -:- For detailed product information, please contact sales. -:

AISI 8625H Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 8625H Steel** #### **1. Overview** AISI 8625H is a **hardenability-controlled (H-grade)** variant of the nickel-chromium-molybdenum alloy steel, specifically engineered to deliver **guaranteed and consistent transformation characteristics** during heat treatment. As a member of the 8600 series case-hardening steels, 8625H features a **higher carbon content** than 8620H/8622H grades, providing **superior core strength and hardenability** while maintaining the excellent toughness imparted by nickel. The "H" designation signifies that the material's end-quench (Jominy) hardenability is certified to fall within a narrow, specified band. This guarantees **exceptional batch-to-batch consistency** in final core properties after carburizing, making it an ideal choice for high-volume production of critical, heavily loaded components where performance uniformity is non-negotiable. #### **2. International Standards & Designations** AISI 8625H is defined by international standards that govern both its chemical composition and its guaranteed hardenability range. | Region/System | Standard Designation | Title / Purpose | | :--- | :--- | :--- | | **USA (AISI/SAE)** | **AISI 8625H, SAE J404 & SAE J1268** | Chemical Composition & Hardenability Bands | | **USA (ASTM)** | **ASTM A304** | Standard Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements | | **USA (ASTM)** | **ASTM A914/A914M** | Steel Bars Subject to Restricted Hardenability Bands | | **UNS Number** | **H86250** | Unified Numbering System for H-Steels | | **Europe (EN)** | **1.6526H / 25NiCrMo2-2H** | Hardenability-controlled Equivalent | | **Heat Treatment** | **SAE AMS-H-6875** | Heat Treatment of Steel, General Requirements | | **Japan (JIS)** | **SNCM420H** (Close Equivalent) | Similar Hardenability-controlled Grade | #### **3. Chemical Composition & Hardenability Guarantee** The chemical composition is tightly controlled to ensure the hardenability consistently falls within the certified "H-band," with carbon content being the key differentiator. **Core Composition (% by Weight, AISI 8625H):** | Element | Content Range | Metallurgical Significance | | :--- | :--- | :--- | | **Carbon (C)** | **0.22 - 0.28** | **Primary differentiator:** Higher carbon provides increased core strength and hardenability versus 8620H/8622H. Tightly controlled for H-band consistency. | | **Manganese (Mn)** | 0.70 - 0.95 | Major hardenability agent; range adjusted to meet precise H-band specifications. | | **Phosphorus (P)** | ≤ 0.035 | Impurity control. | | **Sulfur (S)** | ≤ 0.040 | Impurity control. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; solid solution strengthener. | | **Nickel (Ni)** | 0.35 - 0.75 | Enhances core toughness and hardenability; critical for impact resistance. | | **Chromium (Cr)** | 0.35 - 0.65 | Increases hardenability; promotes wear-resistant carbides in the case. | | **Molybdenum (Mo)** | 0.15 - 0.25 | Strong hardenability element; inhibits grain growth; reduces temper embrittlement risk. | **Key Feature: Guaranteed Hardenability Band** The steel is supplied with certification that its Jominy end-quench test results fall within a published, narrow hardness band at specific distances (e.g., J4, J8, J12). This **guarantees predictable and uniform core hardness** after final carburizing and quenching, minimizing performance variation across production batches. #### **4. Mechanical & Physical Properties** *Properties are highly dependent on the final heat treatment. The following represents typical achievable ranges.* **As-Supplied (Annealed/Normalized) Properties:** * **Hardness:** **156 - 207 HB** (Brinell) * **Tensile Strength:** **540 - 690 MPa** (78 - 100 ksi) * **Machinability:** **~60%** of B1112 steel. **Properties After Case Hardening (Carburized & Hardened):** * **Surface (Case) Properties:** * **Hardness:** **58 - 63 HRC** * **Effective Case Depth:** Typically 0.5 - 2.5 mm, as specified. * **Core Properties (H-Grade Advantage):** * **Hardness:** **40 - 52 HRC** (Higher and more predictable than standard 8625). * **Tensile Strength:** **1250 - 1550 MPa** (181 - 225 ksi) * **Yield Strength:** **1050 - 1350 MPa** (152 - 196 ksi) * **Impact Toughness:** Maintains good values due to nickel, despite high strength. * **Section Size Capability:** Enhanced hardenability allows effective heat treatment of larger sections (up to ~150mm/6" diameter) while maintaining core properties. **Physical Properties (Core):** * **Density:** 7.85 g/cm³ * **Modulus of Elasticity:** 205 GPa * **Poisson's Ratio:** 0.29 * **Coefficient of Thermal Expansion:** 12.4 × 10⁻⁶/°C #### **5. Product Applications** AISI 8625H is specified for high-performance, high-volume components where guaranteed core consistency and high load-bearing capacity are critical. * **Heavy-Duty Transmission Gearing:** Large gears for wind turbine gearboxes, mining shovel drives, heavy industrial reducers, and marine transmissions. * **High-Load Bearing Components:** Large-diameter bearing races and rollers in construction, mining, and energy applications. * **Oil & Gas Equipment:** Critical downhole tools, large valve stems, and high-pressure pump components. * **Heavy Vehicle Components:** Final drive gears, differential carriers, and axle shafts for mining trucks and heavy transport. * **Power Generation:** Gear components for turbine drives and large compressor systems. * **Aerospace Secondary Structures:** Heavily loaded actuator components and landing gear parts where material consistency is mandated. #### **6. Key Characteristics & Advantages** * **Guaranteed Core Property Consistency:** The **primary H-grade advantage**. Eliminates batch-to-batch variation in core hardness and strength, ensuring uniform fatigue life, predictable deformation, and reliable assembly (e.g., press fits). * **High Core Strength & Load Capacity:** The increased carbon content provides greater core strength than 8620H/8622H, offering superior support for the hardened case under extreme bending and contact stresses. * **Excellent Hardenability:** Enables successful through-hardening of large cross-sections, making it suitable for heavy-section components. * **Reduced Manufacturing Risk & Scrap:** Virtually eliminates rejects due to core hardness outliers, providing significant cost savings and production stability. * **Optimized for Automated Production:** Predictable machining and heat treatment response allow for optimized, stable manufacturing processes with minimal quality intervention. * **Superior Fatigue Performance:** The consistent, strong core combined with a hard, compressive-stressed case delivers exceptional resistance to bending and contact fatigue. **Conclusion:** **AISI 8625H represents a premium, reliability-focused engineering material designed for the most demanding case-hardening applications.** It successfully combines the **enhanced strength and hardenability of a higher-carbon grade** with the **batch-to-batch consistency guarantees of the H-grade system**. This makes it an indispensable choice for manufacturers of large, heavily loaded components where performance cannot be left to chance. By specifying 8625H, engineers and producers gain not just a material, but a **comprehensive quality assurance solution** that minimizes variability, reduces total cost of ownership, and ensures that every component—from the first to the ten-thousandth—will perform identically under load. For critical applications in energy, heavy machinery, and transportation sectors, AISI 8625H provides the technical excellence and production reliability needed to meet today's most stringent performance standards. -:- For detailed product information, please contact sales. -: AISI 8625H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5744 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 8625H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8625H Steel Seamless tube -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8625H Steel Seamless tube -:- For detailed product information, please contact sales. -:

Packing of AISI 8625H Steel Seamless tube -:- 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 Seamless tube 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 2215 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