AISI 8625 Steel Seamless tube

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

AISI 8625 Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 8625 Steel** #### **1. Overview** AISI 8625 is a versatile **low-carbon nickel-chromium-molybdenum (Ni-Cr-Mo) alloy steel**, classified within the American Iron and Steel Institute (AISI) 8600 series as a **case-hardening (carburizing) grade**. With a balanced composition centered around **higher carbon content** than the more common AISI 8620, this steel is engineered to deliver **superior core strength and hardenability** while maintaining excellent toughness. After carburizing heat treatment, it develops the characteristic **"hard case, tough core"** microstructure, making it particularly suitable for **medium to heavy-duty components** that require enhanced load-bearing capacity beneath the wear-resistant surface. #### **2. International Standards & Designations** AISI 8625 is recognized under multiple international standards with equivalent designations across different regional systems. | Region/System | Standard Designation | Title / Purpose | | :--- | :--- | :--- | | **USA (AISI/SAE)** | **AISI 8625, SAE J404** | Standard Chemical Composition | | **USA (ASTM)** | **ASTM A322** | Standard Specification for Steel Bars, Alloy, Standard Grades | | **USA (ASTM)** | **ASTM A534** | Carburizing Steels for Anti-Friction Bearings | | **UNS Number** | **G86250** | Unified Numbering System | | **Europe (EN)** | **1.6526 / 25NiCrMo2-2** | Equivalent Material Standard | | **Germany (DIN/W-Nr.)** | **25NiCrMo2 / 1.6526** | Equivalent Designation | | **Japan (JIS)** | **SNCM420** (Close Equivalent) | Similar Material Standard | | **International** | **ISO 683-11: 25NiCrMo2-2** | International Material Standard | #### **3. Chemical Composition** The alloy composition is optimized for good hardenability and core strength, with carbon content being the primary differentiator from lower-numbered grades in the 8600 series. | Element | Content (% by Weight) | Metallurgical Role | | :--- | :--- | :--- | | **Carbon (C)** | **0.23 - 0.28** | **Key feature:** Provides higher core strength and hardenability compared to 8620/8622. Forms the basis for martensitic transformation. | | **Manganese (Mn)** | 0.70 - 0.90 | Enhances hardenability, aids in deoxidation, and strengthens the ferrite matrix. | | **Phosphorus (P)** | ≤ 0.035 | Residual impurity; controlled to minimize cold brittleness. | | **Sulfur (S)** | ≤ 0.040 | Residual impurity; improves machinability but controlled to prevent hot shortness. | | **Silicon (Si)** | 0.15 - 0.35 | Powerful deoxidizer; provides solid solution strengthening. | | **Nickel (Ni)** | 0.40 - 0.70 | **Critical element:** Significantly enhances core toughness and hardenability while lowering ductile-to-brittle transition temperature. | | **Chromium (Cr)** | 0.40 - 0.60 | Increases hardenability depth; promotes formation of hard carbides in the case during carburizing. | | **Molybdenum (Mo)** | 0.15 - 0.25 | Enhances hardenability; reduces susceptibility to temper embrittlement; improves high-temperature strength. | | **Iron (Fe)** | Balance | Base metal. | #### **4. Mechanical & Physical Properties** *Properties vary significantly with condition (annealed, normalized, heat-treated). The following represents typical characteristics.* **Typical Properties in Annealed Condition (Machining Stock):** * **Hardness:** **156 - 207 HB** (Brinell) * **Ultimate Tensile Strength:** **540 - 690 MPa** (78 - 100 ksi) * **Yield Strength:** **400 - 550 MPa** (58 - 80 ksi) * **Elongation:** **20% - 26%** * **Reduction of Area:** **50% - 60%** * **Machinability:** **~60%** of B1112 steel (Good with proper tooling). **Properties After Case Hardening (Carburized & Hardened):** * **Surface Case Hardness:** **58 - 63 HRC** (Rockwell C) * **Effective Case Depth:** Typically 0.5 - 2.0 mm (0.020" - 0.080"), adjustable per process. * **Core Hardness:** **38 - 50 HRC** (Higher than 8620/8622 due to increased carbon content). * **Core Tensile Strength:** **1200 - 1500 MPa** (174 - 218 ksi) * **Core Yield Strength:** **1000 - 1300 MPa** (145 - 189 ksi) * **Impact Toughness:** Good, maintained by nickel content despite higher strength. **Physical Properties:** * **Density:** **7.85 g/cm³** (0.284 lb/in³) * **Modulus of Elasticity:** **205 GPa** (29,700 ksi) * **Poisson's Ratio:** **0.29** * **Thermal Conductivity:** **~44 W/m·K** at 100°C * **Coefficient of Thermal Expansion:** **12.4 × 10⁻⁶/°C** (20-100°C) #### **5. Product Applications** AISI 8625 is employed in applications requiring a robust combination of surface wear resistance and high core strength, particularly where components are subjected to significant bending or torsional stresses. * **Heavy-Duty Gearing:** Medium to large gears for industrial transmissions, mining equipment, agricultural machinery, and heavy vehicle differentials. * **High-Load Bearing Components:** Bearing races and rollers subjected to substantial contact stresses. * **Automotive & Truck Components:** Critical transmission gears, camshafts, and axle shafts in medium to heavy-duty vehicles. * **Oil & Gas Equipment:** Downhole tool components, valve parts, and pump gears requiring durability under high pressure. * **Construction & Mining Machinery:** Pins, bushings, shafts, and final drive components. * **Power Transmission Systems:** Couplings, splined shafts, and sprockets for conveyor systems. #### **6. Key Characteristics & Advantages** * **Enhanced Core Strength & Hardenability:** The higher carbon content (0.23-0.28%) provides significantly greater core strength and hardenability than 8620, enabling use in larger sections or higher-stress applications. * **Excellent Toughness Retention:** Despite higher strength, the nickel content ensures good impact resistance and fracture toughness in the core. * **Superior Load-Bearing Capacity:** The strong core provides excellent support for the hardened case, making it ideal for components experiencing high bending or contact fatigue loads. * **Good Wear & Pitting Resistance:** The carburized case provides excellent surface durability against abrasion and contact fatigue (pitting). * **Good Machinability (Pre-HT):** In the annealed or normalized condition, it can be readily machined into complex shapes. * **Weldability:** Fair with proper procedures (preheat and post-weld heat treatment recommended). * **Versatile Heat Treatment Response:** Responds well to various carburizing methods (gas, liquid, plasma) and quenching techniques. **Conclusion:** **AISI 8625 is a robust and reliable medium-carbon case-hardening steel that occupies an important position between the more common 8620 and the higher-carbon 8630 grades.** Its balanced composition delivers an optimal combination of **surface hardness, core strength, and retained toughness**, making it a preferred choice for engineering components that must withstand both severe surface wear and significant subsurface stresses. The steel's predictable response to carburizing heat treatment and its ability to maintain good toughness at higher strength levels make it a trusted material for demanding applications in heavy machinery, transportation, and industrial equipment sectors. When component designs require greater load capacity than 8620 can provide but the exceptional toughness of nickel-alloyed steel must be maintained, AISI 8625 presents an excellent technical and economic solution. -:- For detailed product information, please contact sales. -: AISI 8625 Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5743 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 8625 Steel Properties -:- For detailed product information, please contact sales. -:

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

Packing of AISI 8625 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 2214 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