AISI 4817H Steel Rod/Bar

AISI 4817H Steel Rod Product Information -:- For detailed product information, please contact sales. -: AISI 4817H Steel Rod Synonyms -:- For detailed product information, please contact sales. -:

AISI 4817H Steel Product Information -:- For detailed product information, please contact sales. -: # Technical Data Sheet: AISI 4817H Steel ## 1. Product Overview **AISI 4817H** is a **hardenability-controlled, high-nickel alloy steel** specifically engineered for **critical case hardening applications** requiring guaranteed and consistent core properties. The **"H" designation** indicates that the steel's chemical composition is precisely controlled to fall within specified hardenability bands as defined by ASTM A304, ensuring predictable and uniform response to heat treatment across all production lots. With its **exceptionally high nickel content (3.25-3.75%)** combined with molybdenum, AISI 4817H delivers **premium core toughness, impact resistance, and fatigue performance** in carburized components. This grade is selected for the most demanding applications where component reliability, dimensional consistency, and resistance to shock loading are paramount, particularly in aerospace, defense, and heavy industrial sectors. ## 2. Material Specifications & Standards * **UNS Designation:** H48170 * **AISI/SAE:** 4817H * **Governing Standard:** **ASTM A304** - *Standard Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements* (the defining standard for "H"-grade steels). * **Additional Material Standards:** * **SAE J404:** Chemical Compositions of SAE Alloy Steels * **ASTM A534:** Standard Specification for Carburizing Steels for Anti-Friction Bearings (commonly specified for bearing applications) * **Heat Treatment Reference Standards:** * **AMS 2759/7:** Carburizing and Carbonitriding (Aerospace) * **SAE J1268:** Heat Treatment of Steel * **International Equivalents:** * **EN/DIN:** 17NiCrMoS6-4+H / 1.6566+H (European designation with hardenability control) * **JIS:** SNCM431H (or similar Japanese classification with hardenability) * **GB:** 17CrNiMo6H (China) ## 3. Chemical Composition (ASTM A304 H-Band Ranges) The composition is tightly controlled within specified ranges to guarantee the required hardenability band. The high nickel content is the defining feature. | Element | Content Range (%) | Metallurgical Significance in 4817H | | :--- | :---: | :--- | | **Carbon (C)** | 0.15 – 0.20 | **Tightly controlled for hardenability.** Provides base core strength while ensuring excellent core toughness after carburizing. | | **Manganese (Mn)** | 0.40 – 0.70 | Enhances hardenability. Range is controlled to ensure consistent hardenability response. | | **Phosphorus (P)** | ≤ 0.035 | Tightly controlled residual element. | | **Sulfur (S)** | ≤ 0.040 | Tightly controlled residual element. Free-machining variants (e.g., 4817RH) with controlled sulfur additions are available. | | **Silicon (Si)** | 0.15 – 0.35 | Deoxidizer; provides solid solution strengthening. | | **Nickel (Ni)** | 3.25 – 3.75 | **Primary alloying element.** **Exceptional toughness driver.** Significantly improves core impact resistance, fracture toughness, and fatigue crack growth resistance. Its control is critical for predictable hardenability and property consistency. | | **Chromium (Cr)** | ≤ 0.20 (residual) | Not a specified alloying element in standard 4817H; kept low as a residual. | | **Molybdenum (Mo)** | 0.20 – 0.30 | **Critical for hardenability and grain control.** Refines austenite grain size during high-temperature cycles, improves hardenability in heavy sections, and reduces susceptibility to temper embrittlement. | **Critical "H"-Grade Requirement:** For AISI 4817H, the steel producer must provide certification that a sample from each heat meets the specified **hardenability band** (e.g., 4817H, Band 2H, 3H) as per ASTM A304, in addition to the chemical composition report. ## 4. Hardenability & Typical Mechanical Properties The "H" grade ensures that the following core properties are **achievable and consistent** for a specified component cross-section. ### 4.1 Jominy Hardenability (Typical): Purchasers specify the required hardenability band. A typical Jominy curve for 4817H shows excellent depth of hardening due to the high alloy content. * **J1 (Surface):** ~40-50 HRC * **J10 (10/16" from quenched end):** ~35-42 HRC * **J20 (20/16" from quenched end):** ~30-36 HRC *(Specific values depend on the ordered H-band).* ### 4.2 Properties in Annealed Condition (Typical for Machining): * **Hardness:** 149 – 187 HB (85 – 93 HRB) * **Tensile Strength:** 515 – 655 MPa (75 – 95 ksi) * **Machinability:** Good (~65% of 1212 steel). Free-machining "RH" grades offer improved machinability. ### 4.3 Properties After Carburizing, Quenching & Tempering (Typical): * **Case (Surface):** 58 – 63 HRC * **Core (Guaranteed by H-band for specified section size):** * **Hardness:** **33 – 40 HRC** (Achievable in larger diameters than standard 4817). * **Tensile Strength:** 1000 – 1250 MPa (145 – 181 ksi) * **Yield Strength:** 800 – 1100 MPa (116 – 160 ksi) * **Elongation:** 12 – 18% * **Impact Toughness (Charpy V):** **Exceptional.** Typically **55 – 85 J (41 – 63 ft·lb)** at room temperature. This is the key performance advantage over lower-nickel grades. ## 5. Key Characteristics & Advantages * **Guaranteed Core Consistency:** The principal advantage. Engineers can design with confidence, knowing the core hardness and strength will meet specifications consistently in production, minimizing the risk of soft cores or excessive distortion. * **Exceptional Toughness:** The high nickel content provides arguably the best core impact and fracture toughness among standard AISI carburizing grades, making it ideal for components subject to severe shock and overload. * **Superior Fatigue Performance:** The combination of a hard case and an exceptionally tough, crack-resistant core results in outstanding bending and contact fatigue life. * **Good Hardenability Depth:** The Ni-Mo combination ensures sufficient hardenability for large, heavy-section components. * **Premium Performance for Critical Parts:** Designed for applications where component failure is not an option and where performance outweighs material cost. ## 6. Typical Applications AISI 4817H is specified for the **most demanding, safety-critical, carburized components**, especially where shock loading and reliability are paramount. * **Aerospace & Defense (Primary Market):** * Critical transmission gears in helicopter main and tail rotors. * High-stress gears and shafts in jet engine accessory drives. * Landing gear components (pins, trunnions, actuators). * Gearing for military vehicle transmissions and turret drives. * **Heavy Industrial & Mining:** * Large gears for cone crushers and grinding mills. * Final drive gears for massive mining shovels and draglines. * Critical components in heavy forging presses. * **Power Generation:** * High-integrity gears for wind turbine gearboxes (planetary stages). * Turbine governor drive components. * **High-Performance Motorsports:** * Gears and differential components for top-level racing (Formula 1, Le Mans prototypes). * **Oil & Gas:** * Heavy-duty bearing components for drilling equipment under severe shock loads. ## 7. Heat Treatment & Processing Notes * **Forging & Annealing:** Standard practices apply. Full annealing is required post-forging for machinability. * **Carburizing:** Standard gas carburizing at 900-925°C (1650-1700°F). Deep case depths are common. * **Quenching:** Typically oil quenched. The guaranteed hardenability ensures proper core transformation in the specified section. * **Tempering:** Essential. Temperatures of 150-230°C (300-450°F) are used, balancing case hardness and core toughness. * **Purchasing Requirement:** The **hardenability band (e.g., 4817H, Band 3H)** must be explicitly specified on the purchase order per ASTM A304. ## 8. Comparison: 4817 vs. 4817H | Feature | **AISI 4817** | **AISI 4817H** | | :--- | :--- | :--- | | **Control Basis** | Chemical composition only. | **Chemical composition AND hardenability (Jominy band).** | | **Certification** | Chemistry report. | Chemistry report **plus** Jominy hardenability test report. | | **Core Consistency** | Standard mill variation; may require more heat treatment adjustment. | **Highly consistent, guaranteed core properties** from lot to lot. | | **Cost** | High (due to Ni content). | **Premium** (due to Ni content plus extra testing and control). | | **Best Use** | Critical applications where some lot-to-lot adjustment is acceptable. | **Ultra-critical applications** where core properties and dimensional consistency **must be guaranteed** in production. | --- **Disclaimer:** This data sheet provides general information. **The specific hardenability band (H-band) is a mandatory purchase specification for AISI 4817H.** Final component properties are dependent on geometry, exact heat treatment, and the specified H-band. Consultation with a qualified metallurgist is essential for component design and specification of this premium engineering material. -:- For detailed product information, please contact sales. -: AISI 4817H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5666 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 4817H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4817H Steel Rod -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4817H Steel Rod -:- For detailed product information, please contact sales. -:

Packing of AISI 4817H Steel Rod -:- 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 2137 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