AISI 4118 Steel Seamless tube,

AISI 4118 Steel Seamless tube, Product Information -:- For detailed product information, please contact sales. -: AISI 4118 Steel Seamless tube, Synonyms -:- For detailed product information, please contact sales. -:

AISI 4118 Steel, Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 4118 Steel** **Overview** AISI 4118 is a versatile, low-carbon case-hardening chromium-molybdenum (Cr-Mo) alloy steel. It is designed to combine a tough, ductile core with an extremely hard, wear-resistant surface layer after carburizing or carbonitriding heat treatment. This “hard shell, soft core” characteristic makes it an ideal choice for components subjected to high surface contact stress, rolling, sliding wear, and fatigue, while requiring good impact resistance and core strength. It offers a favorable balance of performance, processability, and cost-effectiveness. **Key International Standards & Designations** * **AISI / SAE:** 4118 * **UNS:** G41180 * **Germany (DIN):** 1.7139 / 16MnCr5 (slightly different composition, but similar application) * **Europe (EN):** 1.7139 / 16MnCr5 * **Japan (JIS):** SCr415 / SCr420 (closest equivalents) * **Note:** While AISI 4118 is a standardized grade, its closest functional equivalents in different standards may have minor compositional variations. For precise sourcing, UNS G41180 is the universal identifier. **Chemical Composition (Typical, Weight %)** The low carbon content is key for core toughness after case hardening. | Element | Content (%) | Element | Content (%) | | :--- | :--- | :--- | :--- | | **Carbon (C)** | 0.17 - 0.22 | **Molybdenum (Mo)** | 0.08 - 0.15 | | **Manganese (Mn)** | 0.70 - 0.90 | **Phosphorus (P)** | ≤ 0.035 | | **Silicon (Si)** | 0.15 - 0.35 | **Sulfur (S)** | ≤ 0.040 | | **Chromium (Cr)** | 0.40 - 0.60 | **Iron (Fe)** | Balance | *Composition is per AISI/SAE specification. Controlled sulfur (re-sulfurized) versions may exist for improved machinability.* **Physical & Mechanical Properties (Core - in Normalized Condition)** *Properties before case hardening.* * **Density:** 7.85 g/cm³ (0.284 lb/in³) * **Melting Point:** Approx. 1420 - 1520 °C (2590 - 2770 °F) * **Modulus of Elasticity:** 205 GPa (29.7 x 10⁶ psi) * **Thermal Conductivity:** ~42.6 W/m·K (at 100°C) * **Typical Mechanical Properties (Normalized or Annealed):** * **Tensile Strength:** 500 - 700 MPa (73 - 102 ksi) * **Yield Strength (0.2% Offset):** 320 MPa min (46 ksi min) * **Elongation:** 20% min * **Hardness:** 150 - 200 HB * **Hardenability:** Good. The chromium and molybdenum provide sufficient core hardenability for medium-sized parts. **Properties After Case Hardening** * **Surface Hardness:** 58 - 63 HRC (after carburizing/quenching) * **Effective Case Depth:** Variable, typically 0.5 mm to 1.5 mm (0.020" to 0.060") based on process time/temperature. * **Core Hardness:** 25 - 40 HRC (after quenching from carburizing temperature, providing strong support for the hard case). **Product Forms & Applications** AISI 4118 is commonly supplied in the hot-rolled, cold-drawn, or annealed condition for optimal machinability prior to heat treatment. * **Available Forms:** * Round, Hex, and Square Bars * Wire Rods and Coils * Forging Billets * Tubing * **Primary Applications:** (Focused on case-hardened components) * **Automotive & Transportation:** **Gears** (transmission, differential, timing), **sprockets**, **camshafts**, **axle shafts**, **pins**, **bushings**, and clutch components. * **Power Transmission:** Light to medium-duty **gear sets**, **splined shafts**, and drive components in machinery. * **General Machinery:** **Cams**, **rollers**, **liners**, and various **wear-resistant parts** requiring a tough core. * **Fasteners:** High-strength bolts, studs, and special fasteners that benefit from a hardened surface. **Heat Treatment** The primary process for AISI 4118 is **Case Hardening**: 1. **Carburizing or Carbonitriding:** The part is heated (typically 900-950°C / 1650-1740°F) in a carbon-rich atmosphere, allowing carbon to diffuse into the surface, creating a high-carbon steel layer. 2. **Quenching:** Rapidly cooled (usually in oil) from the carburizing temperature or a slightly lower temperature. This transforms the high-carbon surface into hard martensite, while the low-carbon core forms a tougher, lower-hardness martensite/bainite structure. 3. **Tempering:** Typically performed at 150-200°C (300-400°F) to relieve quenching stresses without significantly reducing surface hardness. For carbonitriding, the process is similar but uses an atmosphere containing both carbon and nitrogen, often at a slightly lower temperature, resulting in a harder, more distortion-resistant case. **Why Choose AISI 4118?** * **Excellent Case Hardening Response:** Reliably produces a deep, hard, and wear-resistant surface. * **Strong & Tough Core:** Provides excellent resistance to bending and impact, preventing the hard case from cracking under load. * **Good Machinability (in annealed condition):** Allows for economical production of complex part geometries. * **Good Balance of Performance and Cost:** A widely available and cost-effective choice for a vast range of medium-duty hardened components. * **Good Hardenability:** Suitable for parts with moderate cross-sectional sizes. For detailed information on specific processing guidelines, machinability data, or case depth charts, please consult our technical data sheets or contact our engineering team. -:- For detailed product information, please contact sales. -: AISI 4118 Steel, Specification Dimensions Size： Diameter 20-1000 mm Length <4031 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 4118 Steel, Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4118 Steel Seamless tube, -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4118 Steel Seamless tube, -:- For detailed product information, please contact sales. -:

Packing of AISI 4118 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 502 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