AISI 8642H Steel Foil/Strip

AISI 8642H Steel Foil, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round Product Information -:- For detailed product information, please contact sales. -: AISI 8642H Steel Foil, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round Synonyms -:- For detailed product information, please contact sales. -:

AISI 8642H Steel, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round Product Information -:- For detailed product information, please contact sales. -: # Technical Data Sheet: AISI 8642H Alloy Steel ## H-Grade, Oil Quenched & Intermediate-Temperature Tempered Round Bar --- ### 1. Material Overview **Designation:** AISI 8642H / UNS H86420 **Condition:** Oil Quenched from 845°C (1550°F) + Tempered at 595°C (1100°F) **Form:** Round Bar (Multiple Standard Sizes) **Classification:** Hardenability-Controlled Nickel-Chromium-Molybdenum (Ni-Cr-Mo) Alloy Steel **Key Characteristics:** This specification combines the enhanced hardenability and strength potential of the 8642 composition (0.40-0.45% C) with the precise manufacturing control of the "H" designation. Tempering at 595°C represents the optimal intermediate condition, providing a superior balance of strength and toughness that is both predictable and consistent across production batches. This material is engineered for critical components requiring reliable performance under demanding service conditions, where predictable heat treatment response is essential for manufacturing quality and component reliability. --- ### 2. Standards & Specifications **International Standards Compliance:** - **UNS:** H86420 - **ASTM Standards:** - **A304:** Steel Bars, Alloy, Subject to End-Quench Hardenability Requirements - **A914/A914M:** Steel Bars Subject to Restricted Hardenability Requirements - **A331:** Alloy Steel Bars Subject to Mechanical Property Requirements - **SAE/AISI:** - SAE J1268: Hardenability Bands for H-Grade Steels - SAE J404: Chemical Compositions - **ISO Equivalent:** 683-11 with hardenability controls - **EN (European):** Similar to 1.6546H (34CrNiMo6H) with controlled hardenability - **DIN:** Similar to 34CrNiMo6 with specific hardenability bands --- ### 3. Chemical Composition (H-Grade Controlled) **Guaranteed Composition Ranges (Weight %):** | Element | H-Grade Range | Typical Value | Metallurgical Significance | |---------|---------------|---------------|---------------------------| | **Carbon (C)** | 0.39 - 0.46% | 0.42% | Provides enhanced hardenability and strength vs. 8640H; specifically controlled for consistent response | | **Manganese (Mn)** | 0.70 - 1.05% | 0.87% | Primary hardenability control element within H-band limits | | **Silicon (Si)** | 0.15 - 0.35% | 0.25% | Deoxidizer; controlled for consistent hardenability effects | | **Nickel (Ni)** | 0.35 - 0.75% | 0.55% | Enhances toughness; specifically controlled within H-grade bands | | **Chromium (Cr)** | 0.35 - 0.65% | 0.50% | Provides hardenability and tempering resistance; composition controlled | | **Molybdenum (Mo)** | 0.15 - 0.25% | 0.20% | Critical for suppressing temper embrittlement at intermediate temperatures | | **Phosphorus (P)** | ≤ 0.035% | 0.020% | Minimized for improved toughness | | **Sulfur (S)** | ≤ 0.040% | 0.025% | Standard grade; may be controlled for machinability variants | | **Iron (Fe)** | Balance | Balance | Matrix element | **H-Grade Critical Control Points:** - Carbon specifically controlled to center of 0.42% ±0.03% for consistent hardenability - Manganese range optimized for predictable Jominy curve development - Nickel and chromium maintained within narrower bands than standard grades - All elements controlled to ensure hardenability within SAE J1268 bands --- ### 4. Hardenability Specifications **SAE J1268 Hardenability Band for 8642H:** | Distance from Quenched End | Rockwell C Hardness Range (As-Quenched) | |----------------------------|-----------------------------------------| | 1.5 mm (1/16 inch) | 47-59 HRC | | 3.0 mm (1/8 inch) | 46-58 HRC | | 5.0 mm (3/16 inch) | 44-56 HRC | | 9.5 mm (3/8 inch) | 38-50 HRC | | 12.7 mm (1/2 inch) | 35-47 HRC | | 19.0 mm (3/4 inch) | 30-42 HRC | | 25.4 mm (1 inch) | 26-38 HRC | | 38.1 mm (1.5 inch) | 22-34 HRC | **Heat Treatment Process with H-Grade Controls:** 1. **Austenitizing:** 845°C ± 8°C (1550°F ± 15°F) with precise temperature uniformity 2. **Quenching:** Controlled oil quench with monitored cooling rates 3. **Tempering:** 595°C ± 8°C (1100°F ± 15°F) with extended times for complete transformation 4. **Quality Verification:** Statistical process control throughout **H-Grade Advantages at 595°C Temper:** - Predictable strength development regardless of production batch - Consistent toughness values within narrow ranges - Reduced need for extensive mechanical testing - Guaranteed through-hardening capability for specified diameters --- ### 5. Mechanical Properties **Guaranteed Property Ranges by Diameter (H-Grade Consistency):** | Property | 25 mm (1") Diameter | 50 mm (2") Diameter | 75 mm (3") Diameter | H-Grade Benefit | |----------|---------------------|---------------------|---------------------|-----------------| | **Tensile Strength** | 950-1050 MPa | 920-1020 MPa | 890-990 MPa | ±5% variation max | | **Yield Strength (0.2%)** | 830-930 MPa | 810-910 MPa | 790-890 MPa | Consistent lot-to-lot | | **Elongation** | 16-20% | 17-21% | 18-22% | Predictable ductility | | **Reduction of Area** | 50-60% | 52-62% | 54-64% | Reliable energy absorption | | **Hardness** | 30-34 HRC | 29-33 HRC | 28-32 HRC | Tight control (±2 HRC) | | **Charpy V-Notch (20°C)** | 55-70 J | 57-72 J | 59-74 J | Consistent impact values | | **Charpy V-Notch (-18°C)** | 40-55 J | 42-57 J | 44-59 J | Predictable low-temp behavior | | **Fatigue Limit (10⁷)** | 460-520 MPa | 450-510 MPa | 440-500 MPa | Reliable endurance | **Property Consistency Advantages:** - **Batch-to-Batch Variation:** ≤5% for strength properties - **Positional Uniformity:** ≤3 HRC from surface to center in 75 mm diameter - **Statistical Control:** Properties fall within 2-sigma limits of target values - **Predictable Performance:** Reduced safety factors possible in design **Comparative Performance vs. Standard Grade:** - 30% less variation in mechanical properties - 40% reduction in hardenability scatter - More consistent fatigue performance - Reduced need for extensive testing --- ### 6. Physical Properties | Property | Value | Units | Notes | |----------|-------|-------|-------| | **Density** | 7.85 | g/cm³ | At 20°C | | **Melting Range** | 1420-1465 | °C | Controlled composition reduces range | | **Thermal Conductivity** | 42.0 | W/m·K | At 100°C | | **Specific Heat** | 460 | J/kg·K | At 100°C | | **Thermal Expansion** | 11.5 × 10⁻⁶ | /°C | 20-100°C | | **Modulus of Elasticity** | 205 | GPa | Consistent across batches | | **Electrical Resistivity** | 0.23 | μΩ·m | At 20°C | --- ### 7. Microstructural Characteristics **After 595°C Tempering:** - **Primary Structure:** Fine, uniform tempered martensite - **Carbide Distribution:** Spheroidized carbides evenly dispersed - **Prior Austenite Grain Size:** ASTM 7-8 (controlled for consistency) - **Inclusion Content:** Typically ASTM E45 Method D, ≤2.0 (controlled) - **Microcleanliness:** Enhanced control for H-grade material **H-Grade Microstructural Consistency:** - Uniform transformation behavior across entire cross-section - Consistent carbide size and distribution - Minimal banding or segregation - Predictable response to additional processing --- ### 8. Performance Advantages **H-Grade Specific Benefits:** 1. **Manufacturing Reliability:** Reduced scrap and rework in production 2. **Design Optimization:** Engineers can design closer to material limits 3. **Quality Assurance:** Reduced testing requirements without compromising quality 4. **Supply Chain Consistency:** Multiple suppliers produce identical material 5. **Heat Treatment Predictability:** Consistent results regardless of heat treater **595°C Tempering Advantages:** 1. **Optimal Balance:** Superior strength-toughness combination 2. **Fatigue Performance:** Excellent for components with stress concentrations 3. **Machinability:** Good in heat-treated condition 4. **Dimensional Stability:** Complete stress relief 5. **Service Temperature:** Suitable for moderately elevated temperatures **Application-Specific Benefits:** - Consistent performance in safety-critical components - Reliable fatigue life in dynamically loaded parts - Predictable behavior in harsh environments - Reduced maintenance and inspection requirements --- ### 9. Applications **Automotive & Heavy Vehicle (High Volume Production):** - Heavy truck axle shafts (production consistency critical) - Commercial vehicle transmission components - Large diesel engine crankshafts and connecting rods - Off-highway vehicle final drive components - Mass-produced steering components **Aerospace & Defense (Quality Critical):** - Aircraft landing gear components (secondary structures) - Helicopter rotor shafts and components - Missile launch system structural members - Armored vehicle suspension components - Military vehicle drive train parts **Oil & Gas (Reliability Critical):** - Drill string tool joints and subs - Mud pump fluid end components - Subsea equipment structural parts - Valve stems for high-pressure service - Wellhead equipment components **Power Generation (Long Life Requirements):** - Turbine generator shafting - Large pump shafts for power plants - Wind turbine gearbox components - Hydroelectric turbine shafts - Generator coupling components **Heavy Machinery (Performance Critical):** - Excavator swing mechanism gears - Crane boom foot pins and shafts - Mining equipment drive components - Large press columns and rams - Rolling mill backup rolls **Industrial Equipment (Consistency Critical):** - Large gearbox input/output shafts - Extrusion press components - Injection molding machine tie bars - Machine tool spindles and shafts - Processing equipment drive components --- ### 10. Manufacturing & Processing **Machining Guidelines:** - **Condition:** Can be machined in heat-treated state - **Tools:** Coated carbide recommended for production - **Parameters:** 70-100 m/min speed, 0.20-0.35 mm/rev feed - **Coolant:** Required for optimal results - **H-Grade Benefit:** Consistent tool life and predictable machining behavior **Heat Treatment Quality Control:** - Statistical process control throughout - Temperature uniformity verification - Quench rate monitoring - Hardness pattern verification - Microstructure validation **Welding (When Necessary):** - **Procedure:** Must be qualified for H-grade material - **Preheat:** 200-300°C required - **PWHT:** Temper at 600-650°C mandatory - **Consumables:** Low-hydrogen, matching strength - **Inspection:** Enhanced NDT recommended --- ### 11. Quality Assurance **H-Grade Specific Requirements:** 1. **Jominy Testing:** Each heat must be tested 2. **Chemical Control:** Tighter than standard grades 3. **Statistical Reporting:** Cpk values for critical properties 4. **Traceability:** Enhanced documentation requirements 5. **Process Validation:** Statistical process control data **Testing Protocol:** - Full Jominy curve for each heat - Mechanical testing from multiple locations - Microstructural examination - Non-destructive testing as specified - Statistical analysis of test results **Certification:** - EN 10204 3.2 certificate mandatory - Hardenability test report - Statistical process control data - Full traceability documentation - Heat treatment records --- ### 12. Technical Recommendations **Design with H-Grade Material:** - Can use reduced safety factors due to consistency - Design for optimal material utilization - Consider statistical design approaches - Leverage predictable performance characteristics **Procurement Specification:** ``` MATERIAL: AISI 8642H Alloy Steel HEAT TREATMENT: Q845°C, T595°C SPECIFICATION: ASTM A304, SAE J1268 PROPERTIES: Per H-grade guarantees CERTIFICATION: EN 10204 3.2 with Jominy report TESTING: Statistical property reporting required ``` **Quality Expectations:** - Consistent mechanical properties - Predictable performance - Reduced inspection requirements - Enhanced reliability --- ### 13. Comparative Analysis **vs. Standard 8642 at 595°C:** - 30% less property variation - Predictable hardenability - Consistent heat treatment response - Reduced manufacturing risk **vs. 8640H at Same Temper:** - Higher strength potential - Better hardenability - More consistent in larger sections - Better for strength-critical applications **vs. 4340H:** - Cost-effective alternative - Adequate for many applications - Good toughness-strength balance - Proven performance history --- ### 14. Storage & Handling **Special Considerations for H-Grade:** - Maintain traceability throughout handling - Protect certification documentation - Store with proper identification - Prevent mixing with standard grades **Quality Preservation:** - Controlled storage conditions - Regular condition monitoring - Proper handling procedures - Documentation management --- **Disclaimer:** This technical data sheet provides characteristic values for AISI 8642H steel. H-grade materials provide enhanced consistency but require verification for specific applications. Always consult with materials engineering professionals for critical applications. --- **Document Control** - **Document:** TDS-8642H-595T - **Revision:** 1.0 - **Date:** March 2024 - **Prepared By:** Materials Engineering - **Approved By:** Quality Assurance - **System:** ISO 9001:2015 Certified -:- For detailed product information, please contact sales. -: AISI 8642H Steel, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round Specification Dimensions Size： Diameter 20-1000 mm Length <6358 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 8642H Steel, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8642H Steel Foil, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8642H Steel Foil, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round -:- For detailed product information, please contact sales. -:

Packing of AISI 8642H Steel Foil/Strip, oil quenched 845°C (1550°F), 540°C (1000°F) temper, round -:- 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 2829 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