AISI 8115 Low Alloy Steel Rod/Bar

AISI 8115 Low Alloy Steel Rod, Cold Drawn Bar Product Information -:- For detailed product information, please contact sales. -: AISI 8115 Low Alloy Steel Rod, Cold Drawn Bar Synonyms -:- For detailed product information, please contact sales. -:

AISI 8115 Low Alloy Steel, Cold Drawn Bar Product Information -:- For detailed product information, please contact sales. -: ## **Product Specification: AISI 8115 Low-Alloy Case-Hardening Steel, Cold-Drawn Bar** ### **Product Designation** * **Standard Name:** AISI 8115 / SAE 8115 * **UNS Number:** G81150 * **Condition:** **Cold-Drawn** (to size, with improved surface finish and dimensional accuracy) * **Product Form:** **Round, Square, Hexagonal, or Flat Bar** * **Microstructure:** Typically supplied in a spheroidize-annealed condition prior to drawing, ensuring good machinability and a consistent response to subsequent heat treatment. ### **Overview** AISI 8115 is a low-alloy, **nickel-chromium-molybdenum case-hardening steel**. Its balanced chemistry is engineered to produce a deep, hard case with a very tough and strong core after carburizing and heat treatment. Supplied as a **cold-drawn bar**, this product offers superior surface finish, tight dimensional tolerances, and increased yield strength in the "as-delivered" state compared to hot-rolled bar. This makes it an ideal starting material for precision-machined components that require excellent wear resistance, high fatigue strength, and good impact resistance, particularly in demanding automotive and industrial applications. --- ### **1. Chemical Composition (Typical % by Weight, AISI/SAE Standard)** The alloying elements in 8115 work synergistically to provide deep hardenability and core strength. | Element | Content (%) | Role & Effect | | :--- | :--- | :--- | | **Carbon (C)** | 0.13 - 0.18 | Provides a base for core strength. Low enough to ensure excellent core toughness after case hardening. | | **Manganese (Mn)** | 0.70 - 0.90 | Increases hardenability and solid solution strength. | | **Phosphorus (P)** | ≤ 0.035 | Impurity; kept low. | | **Sulfur (S)** | ≤ 0.040 | Impurity; standard low level ensures good transverse properties. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer and strengthens the ferrite matrix. | | **Nickel (Ni)** | 0.20 - 0.40 | **Primary role: Enhances core toughness.** Refines grain structure and improves impact strength, especially at low temperatures. | | **Chromium (Cr)** | 0.30 - 0.50 | Enhances hardenability and promotes the formation of hard, wear-resistant carbides in the case. | | **Molybdenum (Mo)** | 0.08 - 0.15 | **Key element.** Increases hardenability significantly (especially in the core), improves tempering resistance, and enhances strength at elevated temperatures. | | **Iron (Fe)** | Balance | | --- ### **2. Physical & Mechanical Properties** **A. Physical Properties (Cold-Drawn Bar - Typical)** * **Density:** 7.85 g/cm³ (0.284 lb/in³) * **Elastic Modulus (E):** ~205 GPa (29.7 x 10⁶ psi) * **Poisson's Ratio:** 0.29 * **Thermal Conductivity:** ~52 W/m·K * **Coefficient of Thermal Expansion:** 11.5 x 10⁻⁶ /K (20-100°C) **B. Mechanical Properties (As Cold-Drawn / Annealed)** *The cold-drawing process increases strength and hardness over the annealed state.* * **Hardness (Brinell):** 187 - 229 HB (Typical range for machinable condition) * **Tensile Strength:** 620 - 860 MPa (90 - 125 ksi) * **Yield Strength (0.2% Offset):** 515 MPa (75 ksi) min. * **Elongation in 50 mm:** 15% min. * **Surface Finish:** Excellent (smooth, scale-free surface from the drawing process). * **Dimensional Tolerance:** Meets ASTM A29 cold-drawn bar tolerances (much tighter than hot-rolled). **C. Mechanical Properties (After Carburizing & Heat Treatment)** *Note: Final properties depend on case depth and tempering.* * **Surface Hardness (Case):** 58 - 63 HRC * **Effective Case Depth:** Adjustable, typically 0.5 - 2.0 mm (0.020 - 0.080 in) * **Core Hardness:** 28 - 40 HRC (providing a very strong, tough support for the hard case) * **Core Tensile Strength:** 800 - 1100 MPa (116 - 160 ksi) * **Key Advantage:** The Ni-Cr-Mo combination provides **exceptional core toughness and fatigue strength** for high-load, high-cycle applications. --- ### **3. Product Applications** AISI 8115 cold-drawn bar is specified for precision components where its combination of machinability, post-heat treatment properties, and "as-delivered" dimensional accuracy are valued. * **Automotive Powertrain (Primary Market):** * **High-Stress Gears:** Transmission gears (synchro hubs, sleeves), differential side gears and pinions, transfer case gears. * **Shafts:** Axle shafts, drive shafts, output shafts, and splined shafts. * **Engine Components:** Camshafts, fuel injection pump parts. * **Heavy Machinery & Off-Highway Equipment:** * Gears and pinions in final drives and track systems. * High-wear pins, bushings, and rollers. * **Aerospace:** * Non-critical gears, shafts, and actuator components in landing gear and flight control systems. * **Industrial Equipment:** * High-load gear sets for industrial gearboxes and reducers. * Spindles and tool holders. --- ### **4. International Standards & Designations** AISI 8115 is part of the SAE/AISI system. Its closest equivalents are other nickel-chromium-molybdenum case-hardening steels. | Standard System | Designation | Notes / Key Comparison | | :--- | :--- | :--- | | **SAE / AISI (USA)** | **SAE/AISI 8115** | Standard designation. Part of the "81xx" series (Ni-Cr-Mo). | | **UNS (USA)** | **G81150** | Unified Numbering System. | | **ASTM (USA)** | **ASTM A322** (Grade 8115) | Standard for alloy steel bars. **ASTM A29** covers cold-finished bar tolerances. | | **DIN / EN (Germany/EU)** | **~1.5752 (15NiCr13)** or **1.6523 (18CrMo4)** | Not direct equivalents. 15NiCr13 has higher Ni; 18CrMo4 has no Ni but similar applications. The exact Ni-Cr-Mo balance of 8115 is unique. | | **JIS (Japan)** | **SNC815** | The **closest direct equivalent**. Japanese JIS G4102 standard for nickel-chromium steel. | | **GB (China)** | **No direct equivalent** | Similar grades like 20CrNiMo are used but differ in composition. | --- ### **Processing & Advantages of Cold-Drawn Bar** 1. **Machining:** The cold-drawn condition provides improved machinability over hot-rolled bar due to a more consistent microstructure and better chip-breaking characteristics. The smooth surface also reduces tool wear. 2. **Near-Net-Shape:** Tight tolerances and good straightness reduce machining time and material waste. 3. **Improved Strength:** The cold work imparts higher yield and tensile strength in the as-delivered state, which can be beneficial for handling and some intermediate forming operations. 4. **Subsequent Heat Treatment:** The material must be fully austenitized during carburizing, which will remove the effects of cold work. The final properties are determined by the alloy chemistry and the heat treatment cycle, not the prior cold drawing. ### **Summary** **AISI 8115 Cold-Drawn Bar** is a premium, ready-to-machine form of a high-performance **Ni-Cr-Mo case-hardening steel**. It is selected for applications demanding an optimal balance of core toughness, deep hardenability, and high fatigue strength after carburizing. The cold-drawn production process delivers dimensional precision, a superior surface finish, and improved machinability, making it a cost-effective choice for manufacturing high-volume, precision components such as automotive transmission gears and shafts. Its closest international counterpart, **JIS SNC815**, underscores its role as a globally recognized material for critical, high-stress mechanical parts. -:- For detailed product information, please contact sales. -: AISI 8115 Low Alloy Steel, Cold Drawn Bar Specification Dimensions Size： Diameter 20-1000 mm Length <4142 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 8115 Low Alloy Steel, Cold Drawn Bar Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8115 Low Alloy Steel Rod, Cold Drawn Bar -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8115 Low Alloy Steel Rod, Cold Drawn Bar -:- For detailed product information, please contact sales. -:

Packing of AISI 8115 Low Alloy Steel Rod, Cold Drawn Bar -:- 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 Rod 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 613 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