AISI 6118 Steel Seamless tube

AISI 6118 Steel Seamless tube Product Information -:- For detailed product information, please contact sales. -: AISI 6118 Steel Seamless tube Synonyms -:- For detailed product information, please contact sales. -:

AISI 6118 Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 6118 Low-Alloy Case-Hardening Steel** **Overview** AISI 6118 is a low-alloy, chromium-vanadium case-hardening steel known for its excellent **core toughness and good surface hardenability**. It is primarily designed for **carburizing (case hardening)** processes, which create a hard, wear-resistant outer layer ("case") while maintaining a ductile and impact-resistant inner core. This combination makes it ideal for high-strength, high-fatigue components subjected to heavy loads, shock, and surface wear. It is often supplied in the cold-drawn or annealed condition for optimal machinability prior to heat treatment. --- ### **1. Chemical Composition (Typical % by Weight, AISI Standard)** The balanced alloying elements in 6118 provide the necessary hardenability for both the case and core, while vanadium contributes to grain refinement and toughness. | Element | Content (%) | Role & Effect | | :--- | :--- | :--- | | **Carbon (C)** | 0.16 - 0.21 | Provides base strength. Low enough for good core toughness after carburizing, but sufficient for core hardening. | | **Manganese (Mn)** | 0.50 - 0.70 | Increases hardenability, aids in deoxidation, and improves strength. | | **Phosphorus (P)** | ≤ 0.035 | Impurity; kept low to prevent embrittlement. | | **Sulfur (S)** | 0.08 - 0.13 | **Intentionally added** to form manganese sulfides, which improve machinability (a "resulturized" grade). | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer and strengthens the ferrite matrix. | | **Chromium (Cr)** | 0.50 - 0.70 | Enhances hardenability (particularly for the case depth), promotes formation of hard carbides in the case, and improves tempering resistance. | | **Vanadium (V)** | 0.10 - 0.15 | Strong grain refiner. Inhibits grain growth during high-temperature carburizing, resulting in a finer core microstructure and improved toughness/impact strength. | | **Iron (Fe)** | Balance | | --- ### **2. Physical & Mechanical Properties** **A. Physical Properties (Annealed State)** * **Density:** 7.85 g/cm³ (0.284 lb/in³) * **Elastic Modulus (Young's Modulus):** ~205 GPa (29.7 x 10⁶ psi) * **Poisson's Ratio:** 0.29 * **Thermal Conductivity:** ~51.9 W/m·K * **Coefficient of Thermal Expansion:** 11.5 x 10⁻⁶ /K (20-100°C) **B. Mechanical Properties (Typical, After Carburizing & Heat Treatment)** *Note: Properties vary significantly with exact case depth, carburizing cycle, and final tempering.* * **Surface Hardness (Case):** 58 - 63 HRC (after carburizing and quenching) * **Core Hardness:** 25 - 40 HRC (dependent on part size and quench severity) * **Core Tensile Strength:** 550 - 850 MPa (80 - 123 ksi) * **Core Yield Strength (0.2% Offset):** 400 - 700 MPa (58 - 102 ksi) * **Core Elongation:** 15% - 25% * **Impact Strength (Charpy V-notch, Core):** Good to excellent, a key advantage over higher-carbon through-hardening steels. --- ### **3. Product Applications** AISI 6118 is chosen for components that require a hard, wear-resistant surface coupled with a tough, shock-absorbing core. Common applications include: * **Automotive & Trucking:** * **Gears:** Differential gears, transmission gears, synchronizer hubs, pinions. * **Shafts:** Axle shafts, drive shafts, splined shafts. * **Critical Components:** Crankshafts, steering components, universal joint yokes. * **Heavy Machinery & Off-Highway:** * Heavy-duty gear sets for construction and mining equipment. * Sprockets, rollers, and track links. * High-strength pins and bushings. * **Aerospace & Defense:** * Gears and power transmission components in actuators and auxiliary systems. * **Industrial Equipment:** * High-load, high-cycle gears in gearboxes and reducers. * Camshafts, eccentric shafts, and clutch parts. --- ### **4. International Standards & Designations** AISI 6118 has close equivalents in several international standards systems. The **intentional sulfur content for machinability** is a key distinguishing feature. | Standard System | Designation | Notes / Key Comparison | | :--- | :--- | :--- | | **AISI / SAE (USA)** | **SAE/AISI 6118** | The standard designation. The "61" series indicates chromium-vanadium steels. | | **UNS (USA)** | **G61180** | Unified Numbering System equivalent. | | **ASTM (USA)** | **ASTM A322** (Grade 6118) | Standard specification for hot-rolled or cold-finished alloy steel bars. | | **DIN / EN (Germany/EU)** | **~1.7131 (16MnCr5)** or **1.6523 (18CrMo4)** | *Not a direct equivalent.* The sulfurized version of 6118 is a specific North American grade. For properties, 16MnCr5 or 18CrMo4 are similar but with lower/no S. | | **JIS (Japan)** | **No direct equivalent** | Similar case-hardening grades exist (e.g., SCM series), but the specific 6118 composition with S is not standardized. | | **GB (China)** | **No direct equivalent** | Similar grades like 20CrMnTi serve a comparable purpose but have different alloying. | **Important Note on Equivalents:** While 6118 belongs to the family of Cr-V case-hardening steels (like the former **AISI 6115**), its **resulturized (S-added)** version is less common internationally. Its primary use is in North American manufacturing. Engineers looking for a direct functional substitute in other regions often select a standard case-hardening grade (e.g., **SAE 8620, 4320, or 4118**) or the European grades mentioned above, based on the required core hardenability and size of the part. --- ### **Summary** AISI 6118 is a specialized, resulturized case-hardening steel that offers an excellent balance of **machinability in the annealed state** and **superior performance after carburizing**. The addition of **vanadium** for grain refinement gives it a toughness advantage over many standard case-hardening grades, making it a premium choice for demanding, high-impact applications such as heavy-duty automotive and off-highway gear components. Its specification reflects a need for durability, reliability, and manufacturing efficiency in high-stress mechanical systems. -:- For detailed product information, please contact sales. -: AISI 6118 Steel Specification Dimensions Size： Diameter 20-1000 mm Length <4134 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 6118 Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 6118 Steel Seamless tube -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 6118 Steel Seamless tube -:- For detailed product information, please contact sales. -:

Packing of AISI 6118 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 605 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