AISI 4150H, annealed

AISI 4150H, annealed 815°C (1500°F) Product Information -:- For detailed product information, please contact sales. -: AISI 4150H, annealed 815°C (1500°F) Synonyms -:- For detailed product information, please contact sales. -:

AISI 4150H, annealed 815°C (1500°F) Product Information -:- For detailed product information, please contact sales. -: # **AISI 4150H Steel (Annealed Condition) Product Specification** ## **1. PRODUCT IDENTIFICATION & THERMAL PROCESS** **Product:** AISI 4150H High-Carbon Chromium-Molybdenum Alloy Steel **Material State:** Fully Annealed (Softened) - Hardenability Controlled Grade **Specified Annealing Process:** - **Heating:** 815°C (1500°F) with complete soak - **Cooling:** Controlled slow furnace cooling **Metallurgical Significance:** This full annealing treatment produces the **softest possible condition** for AISI 4150H steel, creating an optimal microstructure for machining and forming operations. The 815°C temperature ensures complete austenitization while minimizing grain growth for this high-carbon alloy (0.48-0.53% C). The subsequent slow furnace cooling promotes maximum spheroidization of carbides and formation of coarse, soft pearlite in a ferrite matrix. This condition provides **maximum machinability and dimensional stability** while preserving the certified hardenability characteristics of the "H" grade, ensuring predictable and consistent response to subsequent heat treatment. ## **2. CHEMICAL COMPOSITION (Hardenability Controlled)** | Element | Composition Range (% by weight) | Role in Annealed Condition & Hardenability Control | | :--- | :--- | :--- | | **Carbon (C)** | **0.48 - 0.53** | **Highest in 41xx-H series.** Forms abundant spheroidized carbides during slow cooling. Provides exceptional hardenability potential but requires precise annealing to ensure machinability. | | **Manganese (Mn)** | 0.75 - 1.10 | **Primary hardenability adjuster.** Range expanded versus standard 4150 to allow precise Jominy curve positioning while maintaining softness in annealed state. | | **Phosphorus (P)** | ≤ 0.030 | Tighter than standard 4150 (≤0.035) for consistent impact properties and machinability. | | **Sulfur (S)** | ≤ 0.030 | Controlled for consistent machinability; may be optimized for free-machining variants. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; minimal effect in annealed condition. | | **Chromium (Cr)** | 0.80 - 1.10 | Forms carbides that readily spheroidize during slow cooling. Major contributor to hardenability potential. | | **Molybdenum (Mo)** | 0.15 - 0.25 | **Critical for hardenability control and microstructure.** Promotes complete spheroidization during annealing and ensures consistent hardenability response. | **Carbon Equivalent (CE) for Weldability:** ~0.85-0.95 (indicates very poor weldability) ## **3. CERTIFIED HARDENABILITY (SAE J1268)** Even in the soft, annealed condition, the material carries certified hardenability data defining its predictable response to quenching. **Standard Hardenability Band for 4150H:** | Jominy Distance (1/16 in.) | As-Quenched Hardness Range, HRC (Min - Max) | | :--- | :--- | | **J1.5** | 58 - 64 | | **J5** | 50 - 58 | | **J10** | 42 - 52 | | **J15** | 36 - 46 | | **J20** | 32 - 42 | **Engineering Value:** This certification guarantees that components machined from this annealed stock will achieve predictable and consistent through-hardening when subsequently heat treated, particularly important for large sections where consistency is critical. ## **4. MICROSTRUCTURE & METALLURGY** **Microstructural Features:** - **Matrix:** Ferrite with fully spheroidized carbides - **Carbide Morphology:** Spheroidal, uniformly dispersed (≥95% spheroidization) - **Carbide Size:** 0.5-2.0 μm diameter - **Grain Size:** ASTM 6-8 (refined by controlled annealing) - **Prior Structure:** Complete消除 of previous working history - **Spheroidization:** Complete, with carbides evenly distributed in ferrite matrix **Annealing Transformation Details:** - **Ac₁:** ~735°C - **Ac₃:** ~780°C - **Soak Time:** 1-2 hours per inch at 815°C - **Critical Cooling:** Slow furnace cooling (typically 10-25°C/hour through 700-500°C range) - **Spheroidization Mechanism:** Dissolution of lamellar carbides followed by precipitation as spheres during slow cooling ## **5. PHYSICAL & MECHANICAL PROPERTIES (Annealed Condition)** * **Physical Properties:** * **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:** 40.0 W/m·K @ 100°C * **Coefficient of Thermal Expansion:** 11.0 µm/m·°C (20-100°C) * **Specific Heat Capacity:** 460 J/kg·K * **Mechanical Properties (Typical for Annealed Condition):** * **Tensile Strength:** 600 - 750 MPa (87,000 - 109,000 psi) * **Yield Strength (0.2% Offset):** 350 - 450 MPa (51,000 - 65,000 psi) * **Elongation (in 50mm):** **22% - 28%** * **Reduction of Area:** **50% - 60%** * **Hardness:** **180 - 220 HB** (Approx. 88-96 HRB) * **Charpy V-Notch Impact (21°C):** 35 - 60 J (26 - 44 ft-lb) * **Machinability Rating:** **Good (65-70% of B1112 standard)** - Remarkable for 0.5% carbon steel * **Fatigue Strength:** ~250-300 MPa ## **6. PRODUCT APPLICATIONS (Annealed Condition)** This condition serves exclusively as **premium machining and forming stock** for ultra-high-performance components requiring guaranteed through-hardening consistency. * **Critical Power Transmission Components:** - **Large gear blanks** for mining, marine, and wind turbine applications - **Heavy shafting** for generator sets and industrial drives - **Differential carriers** and **pinion gears** for heavy equipment * **Oil & Gas Drilling Equipment:** - **Drill collar blanks** requiring predictable through-hardening - **Tool joint pre-forms** for critical downhole tools - **Wellhead component blanks** for high-pressure service * **Heavy Machinery & Mining:** - **Crusher shaft blanks** and **gear forgings** - **Excavator swing mechanism components** - **Large bearing races** and **slewing rings** * **Tooling & Die Manufacturing:** - **Large plastic injection mold bases** - **Die casting die blocks** for high-volume production - **Precision fixture components** requiring stability * **High-Strength Fastener Production:** - **Bolt blanks** and **stud stock** for high-performance fasteners - **Special fastener components** requiring thread rolling after annealing ## **7. INTERNATIONAL STANDARDS & EQUIVALENT GRADES** | Standard / Country | Designation | Equivalent Status | Critical Notes | | :--- | :--- | :--- | :--- | | **AISI/SAE** | **4150H** | Primary Standard | SAE J1268 governs hardenability | | **ASTM** | **A304 Grade 4150H** | US Standard | For bars with hardenability requirements | | **UNS** | **H41500** | Unified Numbering | | | **DIN/EN** | **50CrMo4H (1.7228+H)** | **True equivalent** | 50CrMo4 (0.47-0.55%C) matches carbon range | | **JIS** | **SCM445H** | Japanese H-grade | Specify high carbon range | | **GB** | **50CrMoH / 55CrMoH** | Chinese H-grades | 50CrMoH preferred (0.47-0.54%C) | | **ISO** | **ISO 683-18 Type 50CrMo4** | International | Can specify hardenability requirements | ## **8. PROCESSING & FABRICATION** **Annealing Process Control:** - **Temperature Uniformity:** ±8°C (±15°F) throughout load - **Soak Time:** 2 hours per inch minimum at 815°C - **Cooling Rate Control:** Slow furnace cooling (15-30°C/hour to 500°C) - **Atmosphere:** Protective (endothermic or nitrogen-based) to limit decarburization to <0.15mm - **Loading:** Proper spacing for uniform temperature and cooling **Machinability (Optimal Condition):** - **Tooling:** Carbide grade C2-C4 recommended for production - **Cutting Speed:** 70-100 m/min (230-330 SFM) for turning - **Feed Rate:** 0.15-0.30 mm/rev (0.006-0.012 in/rev) - **Depth of Cut:** Up to 6mm (0.25") for roughing operations - **Chip Control:** Produces broken chips with proper tool geometry - **Surface Finish:** Can achieve 1.6 μm Ra with sharp tools **Forming & Bending:** - **Excellent cold formability** due to spheroidized structure - **Minimum bend radius:** 3-4 × thickness - **Hot forming preferred** for complex shapes - **Springback allowance:** 2-3° required for precision bending **Welding Characteristics:** - **Very poor weldability** due to high carbon equivalent - **Not recommended** in any condition - **If absolutely necessary:** Preheat to 300-350°C, use specialized low-hydrogen electrodes, post-heat immediately to 650°C - **Best practice:** Design to avoid welding; use mechanical fastening instead ## **9. SUBSEQUENT HEAT TREATMENT** **Recommended Manufacturing Sequence:** 1. Receive in fully annealed condition (180-220 HB) 2. Rough machine (leave 2-3mm per side for finish) 3. Stress relieve at 600-650°C for 2 hours/inch (optional but recommended) 4. Finish machine to near-final dimensions 5. Harden: Austenitize at 815-830°C, oil quench 6. Temper: 425-600°C based on final property requirements 7. Final grinding (minimal stock removal) **Critical Heat Treatment Considerations for 4150H:** - **Quench Cracking Risk:** High due to carbon content; use interrupted or marquenching techniques for complex parts - **Tempering:** Double tempering strongly recommended - **Dimensional Change:** Allow 0.1-0.15% growth during hardening - **Straightening:** Hot straightening only (300-400°C) ## **10. QUALITY ASSURANCE** **Mandatory Certification:** 1. **Hardenability Test Report** (Jominy curve per SAE J1268) 2. **Chemical Analysis Certificate** (complete trace elements) 3. **Mechanical Test Report** for annealed condition 4. **Microstructure Report** (spheroidization percentage, grain size) 5. **Heat Treatment Certificate** with full temperature records **Acceptance Criteria:** - **Hardness:** 180-220 HB (fully annealed) - **Spheroidization:** ≥95% spheroidized carbides - **Decarburization:** ≤0.20mm total depth - **Grain Size:** ASTM 6-8 - **Surface Quality:** Free from seams, laps, and rolling defects ## **11. COMPARATIVE ANALYSIS** **vs. Annealed 4140H:** - +40-50 HB higher hardness in annealed state - +15-20% higher tensile strength - Lower machinability (65% vs 75% of B1112) - Significantly greater hardenability depth - Higher final hardness potential (up to 60+ HRC) **vs. Normalized 4150H:** - Softer (180-220 HB vs 240-290 HB) - Better machinability and formability - More dimensional stability during machining - Fully spheroidized vs pearlitic structure **Value of "H" Designation:** - **Essential** for predictable through-hardening of high-carbon steel - Eliminates risk of soft spots in large sections - Guarantees consistent core hardness after quenching - Critical for safety components and high-value parts ## **12. DESIGN & SELECTION GUIDELINES** **When to Specify Annealed 4150H:** - Components >75mm diameter requiring predictable through-hardening - Safety-critical parts where heat treatment consistency is non-negotiable - High-value components where scrap cost from heat treatment failures is unacceptable - Applications requiring certified material traceability and performance - Parts with complex geometries where uniform hardening is challenging **Design Considerations:** - **Section transitions:** Minimum radius = 5mm or 0.5× section thickness - **Machining allowances:** 2-3mm per side for finish grinding after heat treatment - **Stress concentrations:** Avoid sharp corners and sudden changes in cross-section - **Symmetry:** Design symmetrical to minimize heat treatment distortion **Economic Considerations:** - Higher material cost than standard 4150 (due to H-grade certification) - Reduced risk of heat treatment failures and scrap - Optimal for high-value components where reliability justifies cost --- **TECHNICAL SUMMARY:** **AISI 4150H steel annealed at 815°C (1500°F)** represents the **ultimate premium starting material** for manufacturing ultra-high-performance components requiring guaranteed through-hardening consistency. This specific annealing treatment transforms the high-carbon steel into a fully spheroidized, machinable microstructure while preserving exceptional hardenability potential. The "H" grade certification is particularly critical for 4150, as it guarantees predictable hardening behavior in large cross-sections where variations could lead to catastrophic failure. This material condition is specified for the most demanding components in energy, heavy machinery, and critical systems where reliability, predictability, and performance are paramount. When failure is not an option, annealed 4150H provides the material certainty that engineers require for mission-critical designs. -:- For detailed product information, please contact sales. -: AISI 4150H, annealed 815°C (1500°F) Specification Dimensions Size： Diameter 20-1000 mm Length <6234 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 4150H, annealed 815°C (1500°F) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 4150H, annealed 815°C (1500°F) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 4150H, annealed 815°C (1500°F) -:- For detailed product information, please contact sales. -:

Packing of AISI 4150H, annealed 815°C (1500°F) -:- 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 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 2705 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