AISI 4145H Steel Foil/Strip

AISI 4145H Steel Foil Product Information -:- For detailed product information, please contact sales. -: AISI 4145H Steel Foil Synonyms -:- For detailed product information, please contact sales. -:

AISI 4145H Steel Product Information -:- For detailed product information, please contact sales. -: # **AISI 4145H Steel (Hardenability Controlled Grade) Product Specification** ## **1. PRODUCT DEFINITION & TECHNICAL PHILOSOPHY** **Product:** AISI 4145H Alloy Steel **Classification:** High-Carbon Chromium-Molybdenum (Cr-Mo) Hardenability-Grade Steel **Core Technical Principle:** The "H" suffix designates material produced to guaranteed **hardenability band requirements** as per SAE J1268 and ASTM A304 standards. Unlike standard AISI 4145 (controlled by chemical composition only), 4145H is certified to achieve predictable and consistent depth-of-hardening characteristics, ensuring uniform mechanical properties throughout the cross-section of heat-treated components regardless of minor chemical variations between production heats. **Material Position:** AISI 4145H represents the highest carbon/hardenability variant within the 41xx-H series, offering maximum achievable strength and wear resistance for large-diameter components requiring certified through-hardening consistency. ## **2. CHEMICAL COMPOSITION WITH HARDENABILITY CONTROL** Composition ranges are engineered to satisfy both the base 4145 chemistry and the mandatory hardenability band requirements. | Element | Composition Range (% by weight) | Hardenability Control Function | | :--- | :--- | :--- | | **Carbon (C)** | **0.43 - 0.48** | **Primary strength/hardenability determinant.** The elevated carbon content (highest in 41xx-H series) ensures maximum as-quenched hardness. Content is carefully balanced within range to maintain consistent Jominy curve position. | | **Manganese (Mn)** | 0.75 - 1.10 | **Key hardenability adjuster.** Range is intentionally wider than standard 4145 to allow precise hardenability tuning during steelmaking while maintaining the guaranteed H-band. | | **Phosphorus (P)** | ≤ 0.030 | Tighter maximum than standard 4145 (≤0.035) to ensure consistent impact toughness across all production lots. | | **Sulfur (S)** | ≤ 0.030 | Tighter control than standard 4145 for improved transverse ductility and consistency. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; provides secondary strengthening effect. | | **Chromium (Cr)** | 0.80 - 1.10 | **Major alloying element.** Provides strong hardenability increase and promotes fine carbide formation during tempering. Balance with Mo is critical for H-band consistency. | | **Molybdenum (Mo)** | 0.15 - 0.25 | **Essential for hardenability control and tempering response.** Provides maximum hardenability per weight percentage; suppresses temper embrittlement in critical 350-550°C range. | **Hardenability Control Mechanism:** The steel producer may adjust the Mn/Cr/Mo balance within specified limits to ensure each melt's Jominy curve falls within the strict SAE-defined H-band, while the carbon content (primary strength driver) remains consistently high. ## **3. HARDENABILITY BAND SPECIFICATION (SAE J1268)** The guaranteed hardenability range is the defining characteristic and primary value proposition of 4145H. **Standard Hardenability Band for 4145H:** | Jominy Distance (1/16 in.) | Hardness Range, HRC (Minimum - Maximum) | | :--- | :--- | | **J1.5 (Surface Equivalent)** | **57 - 63** | | **J4** | **52 - 60** | | **J7** | **46 - 55** | | **J10** | **40 - 50** | | **J14** | **35 - 45** | | **J20** | **31 - 41** | | **J30** | **27 - 37** | | **J40** | **24 - 34** | **Engineering Significance:** This data allows designers to predict with certainty the **core hardness** of components after quenching. For example, a 100mm (4") diameter bar oil-quenched from 845°C will have a centerline hardness predictable within approximately 6 HRC points. This predictability is impossible with standard 4145. ## **4. PHYSICAL & MECHANICAL PROPERTIES (After Heat Treatment)** * **Physical Properties (Typical):** * **Density:** 7.85 g/cm³ (0.284 lb/in³) * **Melting Point:** ~1405°C (2560°F) * **Modulus of Elasticity:** 205 GPa (29,700 ksi) * **Thermal Conductivity:** 40.5 W/m·K @ 100°C * **Coefficient of Thermal Expansion:** 11.2 µm/m·°C (20-100°C) * **Electrical Resistivity:** 0.24 µΩ·m @ 20°C * **Achievable Mechanical Properties (Example: Oil Quenched + Tempered at 540°C/1000°F):** * **Ultimate Tensile Strength:** 1200 - 1450 MPa (174,000 - 210,000 psi) * **Yield Strength (0.2% Offset):** 1050 - 1300 MPa (152,000 - 188,000 psi) * **Elongation in 50mm:** 11% - 15% * **Reduction of Area:** 35% - 48% * **Hardness:** 36 - 43 HRC (340 - 415 HB) * **Charpy V-Notch Impact (21°C):** 18 - 32 J (13 - 24 ft-lb) * **Fatigue Strength (Rotating Beam, R=-1):** ~550 - 650 MPa ## **5. CRITICAL APPLICATIONS** 4145H is specified for ultra-demanding applications where component failure is catastrophic, and consistency across production lots is mandatory. * **Oil & Gas Exploration & Production:** * **Extra-heavy-weight drill collars** (6-9" OD) for deep directional drilling * **Blow-out preventer (BOP) rams, bodies, and connectors** * **Large-diameter tool joints** and **kick sub** components * **Sucker rods** for high-load pumping applications * **Heavy Power Transmission:** * **Main gear wheels** for industrial gearboxes (cement, mining, power generation) * **Marine propulsion gears** and **stern tubes** * **Large rotor shafts** for wind turbines and hydroelectric generators * **Mining & Mineral Processing:** * **Gyratory crusher main shafts** and **head centers** * **Ball mill trunnions** and **gear blanks** * **Dragline bucket pins** and **shovel dipper handles** * **Heavy Machinery:** * **Large track rollers** and **idlers** for mining excavators (CAT 793/797 class) * **Forging press rams** and **columns** * **Injection molding machine tie bars** and **platens** * **Aerospace & Defense:** * **Landing gear components** for large aircraft (after appropriate certification) * **Armor vehicle suspension components** * **Large missile launch rail components** ## **6. INTERNATIONAL STANDARDS & EQUIVALENT GRADES** | Standard / Country | Designation | Status / Important Note | | :--- | :--- | :--- | | **AISI / SAE (USA)** | **4145H** | Governed by SAE J1268 for hardenability bands. | | **ASTM (USA)** | **A304 (Grade 4145H)** | Standard specification for alloy steel bars subject to hardenability requirements. | | **UNS** | **H41450** | Unified Numbering System designation. | | **DIN / EN (Germany/EU)** | **42CrMo4H (1.7225+H)** | The **"+H" suffix is mandatory** to specify the hardenability-controlled version. | | **JIS (Japan)** | **SCM445H** | Japanese hardenability-grade equivalent (SCM445: 0.42-0.48%C). | | **GB (China)** | **45CrMoH** | Chinese hardenability grade (45CrMo: 0.42-0.50%C). | | **ISO** | **ISO 683-18: Type 42CrMo4** | Can be supplied to hardenability requirements as agreed. | ## **7. HEAT TREATMENT & PROCESSING PROTOCOLS** **Standard Processing Sequence for Finished Components:** 1. **Rough Machine:** Perform in annealed condition (typically 190-220 HB). 2. **Normalize (Optional but Recommended):** 870-900°C (1600-1650°F), air cool. 3. **Finish Machine:** Complete machining to near-final dimensions. 4. **Austenitize:** 830-845°C (1525-1550°F). Soak time: 30-45 min/inch of thickness. 5. **Quench:** **Agitated oil quench** is standard. The guaranteed H-band is based on an oil-quench cooling rate. 6. **Temper:** **Must begin within 1-2 hours of quenching.** Temperature range: **480-620°C (900-1150°F)** for optimal toughness/strength balance. 7. **Final Grinding/Finishing:** Minimal stock removal to achieve final dimensions. **Critical Processing Notes:** * **Section Size Limit:** Capable of through-hardening in oil up to **150mm (6") diameter** with predictable core properties. * **Double Tempering:** Highly recommended (temper, cool to RT, temper again) to ensure complete transformation of retained austenite. * **Stress Relieving:** After heavy machining in annealed state, stress relieve at 595-650°C (1100-1200°F). ## **8. QUALITY ASSURANCE & CERTIFICATION REQUIREMENTS** **Mandatory Documentation (Per Lot):** 1. **Hardenability Test Report:** Certified Jominy curve showing compliance with SAE 4145H band. 2. **Chemical Analysis Certificate:** Ladle and product analysis. 3. **Mechanical Test Report** (if supplied heat-treated). 4. **Grain Size Report:** Typically ASTM 6-8 or finer. **Additional Testing (Often Specified for Critical Applications):** * Ultrasonic Testing (UT) for internal defects * Magnetic Particle Inspection (MPI) for surface defects * Macro-etch testing for soundness * Charpy impact testing at multiple temperatures ## **9. DESIGN & SELECTION CONSIDERATIONS** **When to Specify 4145H vs. Standard 4145:** - Component diameter > 75mm (3") requiring predictable core hardness - Safety-critical or mission-critical applications - Production involving multiple heat treat batches over time - Components with non-uniform sections where consistent hardening is challenging - Applications requiring certified material traceability and performance consistency **Key Advantages:** 1. **Predictable Performance:** Eliminates heat treat variability from component design equations. 2. **Reduced Safety Factors:** Allows more aggressive design due to material consistency. 3. **Improved Reliability:** Minimizes risk of soft spots or inadequate hardening in thick sections. 4. **Quality Assurance:** Mandatory certification provides full material traceability. **Limitations & Cautions:** - **Weldability:** Very poor in heat-treated condition. Not recommended for welded fabrication. - **Cost Premium:** Typically 25-40% higher than standard 4145. - **Notch Sensitivity:** Higher than lower-carbon alloys at equivalent hardness; generous fillet radii essential. - **Machinability:** More difficult than 4140H/4142H due to higher carbon content. ## **10. CONCLUSION** **AISI 4145H steel** represents the **pinnacle of predictable high-strength engineering materials** within the Cr-Mo alloy family. By trading simple chemical specifications for guaranteed performance-based hardenability, it provides engineers with unmatched certainty in designing large, heavily loaded components. This material is specified not merely for its high strength, but for the **certifiable consistency** of that strength throughout massive cross-sections—a critical requirement in energy, mining, and heavy machinery applications where component failure results in extraordinary economic loss or safety hazards. The "H" designation is effectively an insurance policy, ensuring that multi-ton components will perform identically whether produced today or ten years from now, making 4145H the material of choice when failure is not an option. -:- For detailed product information, please contact sales. -: AISI 4145H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6217 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 4145H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4145H Steel Foil -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4145H Steel Foil -:- For detailed product information, please contact sales. -:

Packing of AISI 4145H Steel Foil/Strip -:- 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 Foil/Strip 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 2688 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