AISI 6120 Steel Seamless tube (UNS G61200)

AISI 6120 Steel Seamless tube (UNS G61200) Product Information -:- For detailed product information, please contact sales. -: AISI 6120 Steel Seamless tube (UNS G61200) Synonyms -:- For detailed product information, please contact sales. -:

AISI 6120 Steel (UNS G61200) Product Information -:- For detailed product information, please contact sales. -: ## **Product Introduction: AISI 6120 (UNS G61200) Chromium-Vanadium Case-Hardening Steel** ### **Overview** AISI 6120 is a versatile **low-alloy chromium-vanadium steel** primarily engineered for **case hardening (carburizing)** applications. It belongs to the same family as AISI 6118 but with a distinctively **lower sulfur content**, making it a **non-resulturized** grade. This key difference prioritizes **improved transverse ductility, impact toughness, and fatigue strength** over free-machining characteristics. After carburizing and heat treatment, it achieves an excellent combination of a very hard, wear-resistant surface and a strong, tough core, ideal for high-stress, high-reliability components. --- ### **1. Chemical Composition (Typical % by Weight, AISI/SAE Standard)** The balanced alloying elements of 6120 provide good hardenability for effective case formation and core strengthening, while vanadium ensures a fine-grained microstructure. | Element | Content (%) | Role & Effect | | :--- | :--- | :--- | | **Carbon (C)** | 0.17 - 0.22 | Provides base strength for the core. Optimal range for achieving a tough core after carburizing. | | **Manganese (Mn)** | 0.70 - 0.90 | A key hardenability enhancer. Higher manganese range compared to some grades provides good through-hardening response for moderate sections. | | **Phosphorus (P)** | ≤ 0.035 | Impurity; kept low to prevent embrittlement. | | **Sulfur (S)** | ≤ 0.040 | **Key Differentiator:** Kept at low, standard impurity levels. This results in fewer manganese sulfide inclusions, leading to **superior transverse mechanical properties and fatigue resistance** compared to resulturized grades like 6118. | | **Silicon (Si)** | 0.15 - 0.35 | Acts as a potent deoxidizer during steelmaking and provides solid solution strengthening. | | **Chromium (Cr)** | 0.50 - 0.70 | Enhances hardenability, promotes the formation of hard carbides in the case for wear resistance, and improves tempering resistance. | | **Vanadium (V)** | 0.10 - 0.15 | A strong grain refiner. Inhibits austenite grain growth during the high-temperature carburizing cycle, resulting in a finer final microstructure that enhances **core toughness and fatigue 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:** ~51.5 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: Final properties are highly dependent on the component's cross-sectional size and the specific heat treatment parameters (carburizing cycle, quench medium, tempering temperature).* * **Surface Hardness (Case):** 58 - 64 HRC * **Core Hardness:** 25 - 40 HRC * **Core Tensile Strength:** 600 - 900 MPa (87 - 130 ksi) * **Core Yield Strength (0.2% Offset):** 450 - 750 MPa (65 - 109 ksi) * **Core Elongation:** 15% - 25% * **Impact Strength (Charpy V-notch, Core):** **Excellent.** The combination of low sulfur and vanadium grain refinement gives 6120 superior toughness, especially in the transverse direction, making it resistant to shock and overload. --- ### **3. Product Applications** AISI 6120 is selected for applications where **high fatigue strength, impact resistance, and directional uniformity of properties are critical**. Its non-resulturized nature makes it preferred over 6118 for the most demanding components. * **High-Performance Automotive & Racing:** * Gears for manual transmissions and limited-slip differentials. * High-stress axle shafts, drive shafts, and stub axles. * Camshafts and valve train components. * **Aerospace & Defense:** * Gears, shafts, and actuation components in aircraft control systems, landing gear mechanisms, and auxiliary power units (APUs). * Critical pins, bolts, and linkages. * **Heavy Machinery & Industrial Gearboxes:** * High-torque, large-diameter gears subject to shock loads (e.g., mining equipment, heavy-duty presses). * Splined shafts and spindles. * **Tooling & Special Components:** * Dies, molds, and fixtures requiring a tough core with a hard surface. * High-wear machine components like guides and slides. --- ### **4. International Standards & Designations** AISI 6120 is recognized under several standard systems, though exact chemical equivalents may vary slightly. | Standard System | Designation | Notes / Key Comparison | | :--- | :--- | :--- | | **SAE / AISI (USA)** | **SAE/AISI 6120** | The standard designation in the "61xx" series (Cr-V steels). | | **UNS (USA)** | **G61200** | Unified Numbering System designation. | | **ASTM (USA)** | **ASTM A322** (Grade 6120) | Standard specification for hot-rolled or cold-finished alloy steel bars. | | **DIN / EN (Germany/EU)** | **~1.7131 (16MnCr5)** or **1.6523 (18CrMo4)** | The closest functional equivalents. **Not direct matches** as European grades have different vanadium specifications. 16MnCr5 is a common case-hardening grade with similar Mn-Cr levels. | | **JIS (Japan)** | **No direct equivalent** | The Japanese JIS standard does not have a direct counterpart with this specific Cr-V combination for case hardening. Grades like **SCM420** or **SMnC420** serve similar purposes. | | **GB (China)** | **No direct equivalent** | Similar case-hardening grades like **20CrMnTi** are used, but with Ti instead of V for grain refinement. | **Key Distinction from 6118:** The primary difference lies in sulfur content. **AISI 6118** is a **resulturized (S: 0.08-0.13%)** grade for improved machinability. **AISI 6120** is a **non-resulturized (S: ≤0.040%)** grade for improved mechanical properties, particularly transverse toughness and fatigue strength. --- ### **Summary** AISI 6120 (UNS G61200) is a high-quality, **toughness-optimized case-hardening steel**. Its defining characteristics—**low sulfur content and vanadium addition**—make it an excellent choice for components subjected to severe dynamic loads, impact, and high-cycle fatigue. While its machinability in the annealed state is less optimal than resulturized grades, its **post-heat-treatment mechanical properties are superior**, justifying its use in critical automotive, aerospace, and heavy industrial applications where reliability and performance under stress are non-negotiable. -:- For detailed product information, please contact sales. -: AISI 6120 Steel (UNS G61200) Specification Dimensions Size： Diameter 20-1000 mm Length <4136 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 6120 Steel (UNS G61200) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 6120 Steel Seamless tube (UNS G61200) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 6120 Steel Seamless tube (UNS G61200) -:- For detailed product information, please contact sales. -:

Packing of AISI 6120 Steel Seamless tube (UNS G61200) -:- 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 607 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