AISI 4720H Steel Wire

AISI 4720H Steel Wire Product Information -:- For detailed product information, please contact sales. -: AISI 4720H Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

AISI 4720H Steel Product Information -:- For detailed product information, please contact sales. -: # Technical Data Sheet: AISI 4720H Steel ## 1. Product Overview **AISI 4720H** is a **hardenability-controlled** nickel-chromium-molybdenum alloy steel specifically engineered for **carburizing applications** where consistent and predictable core properties are critical. The **"H" designation** signifies that the steel's chemical composition is controlled within specified limits to guarantee a defined range of hardenability as measured by the Jominy end-quench test (per ASTM A304). This ensures that components, especially in medium to large cross-sections, will achieve uniform and specified core hardness, strength, and microstructure after heat treatment, regardless of normal production lot-to-lot chemistry variations. AISI 4720H offers an excellent balance of core toughness (from nickel), hardenability (from Cr and Mo), and wear resistance after carburizing. ## 2. Material Specifications & Standards * **UNS Designation:** H47200 * **AISI / SAE:** 4720H * **Governing Standard:** **ASTM A304** - *Standard Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements*. This is the defining standard for all "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 * **Common Heat Treatment Standards:** * **SAE J1268:** Heat Treatment of Steel * **AMS 2759/7:** Carburizing and Carbonitriding (Aerospace) * **International Equivalents:** * **EN/DIN:** 20NiCrMoS2-2+H (Similar to 1.6523+H band) * **JIS:** SNCM220H (Japanese standard often groups 4620H/4720H types) * **GB:** 20CrNiMoH (China) ## 3. Chemical Composition (ASTM A304 H-Band Ranges) The composition is tightly controlled within broader bands than standard 4720 to ensure consistent hardenability. The actual aim chemistry is adjusted by the producer to hit the target Jominy curve. | Element | Content Range (%) | Primary Metallurgical Function in 4720H | | :--- | :---: | :--- | | **Carbon (C)** | 0.17 – 0.22 | **Primary hardenability control.** Provides base core strength. The narrow range is critical for predictable response. | | **Manganese (Mn)** | 0.50 – 0.70 | Enhances hardenability and strength. Range controlled for consistency. | | **Phosphorus (P)** | ≤ 0.035 | Residual, tightly controlled. | | **Sulfur (S)** | ≤ 0.040 | Residual, tightly controlled. May be specified as leaded (L) or other variants for machinability. | | **Silicon (Si)** | 0.15 – 0.35 | Deoxidizer, provides solid solution strengthening. | | **Nickel (Ni)** | 0.90 – 1.20 | **Key for toughness.** Significantly improves core impact resistance and ductility. Its range is managed to control hardenability. | | **Chromium (Cr)** | 0.35 – 0.55 | Increases hardenability; promotes wear-resistant carbides in the case. | | **Molybdenum (Mo)** | 0.15 – 0.25 | **Critical for hardenability & grain control.** Refines grain, improves hardenability in heavy sections, reduces temper embrittlement. Its control is vital for deep hardening. | **Key Point:** For AISI 4720H, the producer must certify that a sample from each heat of steel meets the hardenability requirements (Jominy band) specified by the purchaser, in addition to the chemical composition. ## 4. Hardenability & Typical Mechanical Properties Properties are a function of the final heat treatment. The "H" grade ensures these properties are achievable consistently in the specified section size. ### 4.1 Jominy Hardenability: Purchasers specify a **hardenability band** (e.g., 4720H, Band 3H). A typical Jominy curve for 4720H shows good depth of hardening: * **J1 (Surface):** ~45-55 HRC * **J6 (6/16" from quenched end):** ~40-48 HRC * **J12 (12/16" from quenched end):** ~30-38 HRC *(Exact values depend on the specific H-band ordered).* ### 4.2 Properties in Annealed Condition (Typical for Machining): * **Hardness:** 170 – 212 HB * **Tensile Strength:** 550 – 690 MPa (80 – 100 ksi) * **Machinability:** Good (~60% of 1212 steel). Free-machining variants (4720RH) are available. ### 4.3 Properties After Standard Carburizing, Quenching & Tempering: * **Case (Surface):** 58 – 63 HRC * **Core (Dependent on section size and H-band):** * **Hardness:** **35 – 45 HRC** (Achievable in larger diameters than standard 4720 due to guaranteed hardenability). * **Tensile Strength:** 1000 – 1300 MPa (145 – 189 ksi) * **Yield Strength:** 850 – 1150 MPa (123 – 167 ksi) * **Elongation:** 10% – 15% * **Impact Toughness (Charpy V):** **Excellent.** Typically 35 – 55 J at room temperature, a major advantage for shock-loaded parts. ## 5. Key Characteristics & Advantages * **Guaranteed Core Properties:** The principal advantage. Designers can reliably specify core hardness and strength for a given part diameter, minimizing risk of soft cores in production. * **Excellent Toughness:** Inherited from the Ni-Cr-Mo alloy system, providing superior resistance to impact and shock loading compared to lower-nickel grades. * **Consistent Performance:** Reduces heat treatment variability in mass production, leading to fewer rejects and more reliable component performance. * **Suitable for Larger Sections:** The controlled hardenability makes 4720H a preferred choice over standard 4720 for components with larger cross-sections where full hardening is critical. * **Good Wear & Fatigue Resistance:** Performs excellently after carburizing, providing a hard, durable case resistant to pitting and bending fatigue. ## 6. Typical Applications AISI 4720H is specified for **high-performance, critical carburized components** where core integrity is non-negotiable, especially in automotive, heavy equipment, and industrial gearing. * **Automotive & Heavy Truck:** High-load differential gears and pinions, transmission gears (especially for larger vehicles), axle shafts, power take-off (PTO) components. * **Heavy Equipment & Mining:** Large gears and pinions for final drives, track system components, roller and idler shafts, crusher components. * **Industrial Gearboxes:** Gearing for wind turbine gearboxes (non-planetary stages), large industrial reducers, marine propulsion gears. * **Agriculture:** High-torque drivetrain components for large tractors and combines. * **Oil & Gas:** Heavy-duty bearings, tool joints, and drilling equipment components subject to shock loads. ## 7. Heat Treatment & Processing Notes * **Forging & Annealing:** Standard practice. Annealing is required after hot working to ensure machinability. * **Carburizing:** Standard gas carburizing at 900-930°C (1650-1705°F). * **Quenching:** Typically oil quenched. The guaranteed hardenability ensures proper martensitic transformation in the core at the center of the specified section size. * **Tempering:** Essential after quenching. Temperatures of 150-230°C (300-450°F) are common, depending on the desired hardness-toughness balance. * **Purchasing Specification:** When ordering 4720H, the **hardenability band (e.g., 2H, 3H, 4H)** must be specified on the purchase order per ASTM A304, based on the component's design requirements and section size. ## 8. Comparison: 4720 vs. 4720H | Feature | **AISI 4720** | **AISI 4720H** | | :--- | :--- | :--- | | **Primary Control** | Chemical composition only. | **Chemical composition AND hardenability.** | | **Certification** | Chemistry report. | Chemistry report **plus** Jominy hardenability test report. | | **Consistency** | Standard industry variation. | **Highly consistent** core properties from lot to lot. | | **Cost** | Standard. | **Premium** (due to extra testing and tighter control). | | **Best For** | General applications, smaller sections, where some property variation is acceptable. | **Critical applications, larger sections, mass production** where core properties must be guaranteed. | --- **Disclaimer:** This data sheet provides general information. **The specific hardenability band (H-band) is a critical purchase requirement for AISI 4720H.** Final performance depends on component geometry, exact heat treatment cycle, and the specified H-band. Consultation with a metallurgist or material engineer is essential for component design and specification. -:- For detailed product information, please contact sales. -: AISI 4720H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5662 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 4720H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4720H Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4720H Steel Wire -:- For detailed product information, please contact sales. -:

Packing of AISI 4720H Steel Wire -:- 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 Wire 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 2133 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