AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342)

AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342) Product Information -:- For detailed product information, please contact sales. -: AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type M42 Molybdenum High Speed Tool Steel (UNS T11342) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type M42 Ultra-High-Cobalt Super High-Speed Tool Steel (UNS T11342)** ## **Overview** AISI Type M42 is an **ultra-high-cobalt, molybdenum-based super high-speed steel** widely regarded as the **premium standard for high-performance HSS applications**. With its **exceptional cobalt content (7.50-9.50%)** and optimized carbon-vanadium balance, M42 delivers **superior hot hardness, red hardness, and cutting performance** at extreme temperatures. This grade represents the **pinnacle of conventional HSS technology**, offering the best balance of high-temperature performance, wear resistance, and grindability among cobalt HSS grades, making it the preferred choice for the most demanding machining applications worldwide. **Key Advantages:** - **Exceptional Hot Hardness:** Maintains cutting edge at temperatures up to 600-650°C (1110-1200°F) - **Superior Red Hardness:** Outstanding high-temperature hardness retention - **Excellent Thermal Conductivity:** High cobalt content significantly improves heat dissipation - **Good Grindability:** Reasonably grindable for a high-cobalt grade - **Proven Reliability:** Extensive industry experience and application validation - **Wide Acceptance:** Industry standard for premium HSS applications **Primary Considerations:** - **High Cost:** Significant premium over standard HSS grades - **Reduced Toughness:** Lower impact resistance than non-cobalt grades - **Cobalt Price Sensitivity:** Cost fluctuates with cobalt market prices - **Processing Sensitivity:** Requires precise heat treatment control ## **International Designations & Standards** | Standard System | Designation | Note | |----------------|-------------|------| | **AISI/SAE (USA)** | M42 | Primary specification | | **UNS (USA)** | T11342 | Unified numbering system | | **ASTM (USA)** | A600 | High-Speed Tool Steel Standard | | **ISO (International)** | **HS2-9-1-8** | International standard designation | | **DIN (Germany)** | 1.3247 | Standard M42 equivalent | | **JIS (Japan)** | SKH59 | Japanese premium HSS | | **BS (UK)** | **BM42** | British standard M42 | | **GB (China)** | W2Mo9Cr4VCo8 | Chinese super HSS | | **AFNOR (France)** | Z85WDCV09-02-04-01-08 | French designation | *Note: M42 is universally recognized as the premium cobalt HSS grade and serves as the benchmark for high-performance cutting applications.* --- ## **1. Chemical Composition (Typical, Weight %)** M42's composition is optimized for maximum high-temperature performance with balanced grindability. | Element | Content (%) | Role & Metallurgical Effect | |---------|-------------|-----------------------------| | **Carbon (C)** | 1.05 - 1.15 | High carbon content to balance extensive carbide formation and maintain matrix hardness at elevated temperatures. | | **Cobalt (Co)** | 7.50 - 9.50 | **Ultra-high cobalt content.** Dramatically increases red hardness (30-40% over M2), improves thermal conductivity (40-50% over M2), enhances secondary hardening, reduces retained austenite. | | **Molybdenum (Mo)** | 9.00 - 10.00 | **Very high molybdenum.** Primary carbide former providing cost-effective hot hardness in this tungsten-lean composition. | | **Tungsten (W)** | 1.15 - 1.85 | Lower than conventional HSS; works synergistically with molybdenum. | | **Chromium (Cr)** | 3.50 - 4.25 | Standard for hardenability and oxidation resistance. | | **Vanadium (V)** | 0.95 - 1.35 | Moderate level to maintain good grindability while providing adequate wear resistance. | | **Silicon (Si)** | 0.15 - 0.50 | Deoxidizer and matrix strengthener. | | **Manganese (Mn)** | 0.15 - 0.40 | Enhances hardenability. | | **Sulfur (S)** | ≤0.030 | Residual impurity. | | **Phosphorus (P)** | ≤0.030 | Residual impurity. | | **Iron (Fe)** | Balance | Matrix element. | **Metallurgical Characteristics:** - **Cobalt Distribution:** Primarily in solid solution, significantly enhancing matrix strength - **Carbide Types:** M₆C (Mo/W-rich), MC (V-rich), M₂₃C₆ (Cr-rich) - **Carbide Volume:** ~10-14% - **Austenitizing Temperature:** 1175-1215°C (2145-2220°F) --- ## **2. Physical & Mechanical Properties** ### **Physical Properties** | Property | Typical Value | Conditions/Notes | |----------|---------------|------------------| | **Density** | 8.20 - 8.30 g/cm³ | At 20°C (68°F) | | **Melting Range** | 1350 - 1400°C (2460 - 2550°F) | | | **Thermal Conductivity** | 29 - 34 W/m·K | At 20°C (68°F) - 40-50% higher than M2 | | **Specific Heat Capacity** | 410 - 450 J/kg·K | At 20°C (68°F) | | **Coefficient of Thermal Expansion** | 10.6 - 11.4 × 10⁻⁶/K | 20-600°C (68-1110°F) range | | **Electrical Resistivity** | 0.40 - 0.48 μΩ·m | At 20°C (68°F) | | **Elastic Modulus** | 210 - 220 GPa (30.5 - 31.9 × 10⁶ psi) | At room temperature | | **Thermal Diffusivity** | 7.5 - 8.5 mm²/s | At 20°C (68°F) - Excellent heat dissipation | ### **Mechanical Properties (Properly Heat-Treated)** | Property | Value Range | Heat Treatment Condition | |----------|-------------|--------------------------| | **Hardness (Annealed)** | 235 - 277 HB | Annealed condition | | **Hardness (Hardened)** | 66 - 69 HRC | Triple tempered condition | | **Hot Hardness (600°C)** | 58 - 61 HRC | After 4 hours at temperature | | **Transverse Rupture Strength** | 3000 - 3600 MPa (435 - 522 ksi) | At 67-68 HRC | | **Compressive Strength** | 3900 - 4500 MPa (566 - 653 ksi) | At 67-68 HRC | | **Impact Toughness (Charpy)** | 10 - 18 J (7.4 - 13.3 ft·lb) | At 67-68 HRC | | **Young's Modulus** | 210 - 220 GPa (30.5 - 31.9 × 10⁶ psi) | At room temperature | | **Fatigue Strength** | 800 - 950 MPa (116 - 138 ksi) | Rotating bending, 10⁷ cycles | ### **High-Temperature Performance Comparison** | Temperature | M42 Hardness (HRC) | M35 Hardness (HRC) | M2 Hardness (HRC) | Performance Advantage vs M2 | |-------------|---------------------|---------------------|--------------------|----------------------------| | **20°C (68°F)** | 67-68.5 | 65-66.5 | 64-65 | +3.0-3.5 HRC | | **300°C (570°F)** | 63-65 | 62-64 | 60-62 | +3.0-3.5 HRC | | **450°C (840°F)** | 59-62 | 58-61 | 56-58 | +3.0-4.0 HRC | | **550°C (1020°F)** | 55-58 | 54-57 | 52-54 | +3.0-4.0 HRC | | **600°C (1110°F)** | 51-54 | 50-53 | 48-50 | +3.0-4.0 HRC | | **650°C (1200°F)** | 47-50 | 46-49 | 44-46 | +3.0-4.0 HRC | ### **Performance Metrics** - **Red Hardness Improvement:** 35-45% over M2 at 600°C - **Thermal Conductivity Increase:** 40-50% over M2 - **Cutting Speed Potential:** 40-80% higher than M2 - **Tool Life Expectancy:** 3-6x M2 in high-temperature applications - **Maximum Service Temperature:** ~650°C (1200°F) ### **Grindability Characteristics** - **Relative Grindability:** 70-80% (compared to M2 = 100%) - **Wheel Selection:** Premium aluminum oxide or CBN - **Wheel Life:** 50-70% of M2 grinding - **Power Requirement:** 20-30% higher than M2 - **Surface Finish:** Good achievable with proper technique --- ## **3. Product Applications** ### **Primary Application Areas** **1. Premium Cutting Tools (60% of usage):** - **Drills** for heat-resistant alloys, stainless steels, titanium - **End mills** for high-temperature and high-speed operations - **Taps** for difficult-to-machine materials - **Reamers** requiring precision at elevated temperatures **2. High-Performance Production Tools (25%):** - **Gear hobs** for aerospace and automotive applications - **Broaches** for production machining of tough materials - **Milling cutters** for continuous high-performance operations - **Form tools** requiring consistent high-temperature performance **3. Specialized Applications (15%):** - Cutting tools for **hardened steels** (50-55 HRC) - Tools for **high-temperature superalloys** - **High-speed machining** of alloy steels - **Critical aerospace and medical** component machining ### **Industry Application Distribution** | Industry | Market Share | Typical Applications | |----------|--------------|---------------------| | **Aerospace** | 35% | Drills, end mills for titanium/nickel alloys | | **Automotive (High-Perf)** | 25% | Gear cutters, form tools, specialized drills | | **General Machining** | 20% | Premium drills, taps, end mills for difficult materials | | **Medical** | 10% | Surgical instrument manufacturing, implant machining | | **Tool & Die** | 10% | Hard milling cutters, precision tooling | ### **Recommended Cutting Parameters** | Work Material | Cutting Speed (m/min) | Feed (mm/tooth) | vs M2 Improvement | Application Notes | |---------------|----------------------|-----------------|-------------------|------------------| | **Inconel 718** | 25-45 | 0.06-0.15 | +40-60% | High-pressure coolant essential | | **Titanium 6Al-4V** | 40-70 | 0.10-0.25 | +35-55% | Copious coolant required | | **Stainless Steel 316** | 35-60 | 0.10-0.25 | +30-50% | Enhanced coolant recommended | | **Hardened Steel (45-50HRC)** | 45-75 | 0.08-0.20 | +25-40% | Oil-based coolant preferred | | **High-Temp Alloys** | 20-40 | 0.05-0.12 | +50-80% | Specialized cooling strategies | --- ## **4. Heat Treatment Guidelines** ### **Annealing** - **Temperature:** 850-880°C (1560-1615°F) - **Soaking Time:** 2-4 hours - **Cooling Rate:** ≤15°C/hr to 540°C, then air cool - **Resulting Hardness:** 235-277 HB - **Atmosphere:** Protective atmosphere recommended ### **Stress Relieving** - **After Rough Machining:** 600-650°C (1110-1200°F), 2 hours - **After Rough Grinding:** 550-600°C (1020-1110°F), 1 hour - **Cooling:** Slow furnace cool ### **Hardening Process** 1. **Preheating (Critical):** - **First Stage:** 450-550°C (840-1020°F) - **Second Stage:** 800-850°C (1470-1560°F) - **Third Stage:** 1050-1100°C (1920-2010°F) - Recommended for complex tools 2. **Austenitizing:** - **Temperature:** 1175-1215°C (2145-2220°F) - **Soaking Time:** 2-5 minutes per 25mm thickness - **Atmosphere:** **Vacuum or salt bath strongly recommended** - **Protection:** Pack methods if atmosphere control unavailable 3. **Quenching:** - **Oil Quench:** Fast oil, 40-60°C, vigorous agitation - **Salt Bath Marquench:** 500-550°C, equalize, then air cool (preferred) - **Press Quenching:** For flat tools to minimize distortion ### **Tempering (Triple Temper Minimum)** - **First Temper:** Begin at 60-80°C (140-175°F) after quenching - **Temperature:** 540-570°C (1000-1060°F) - **Cycles:** **Minimum 3 tempers, 4 recommended for critical tools** - **Duration:** 1-2 hours per temper - **Cooling:** Air cool completely between tempers - **Final Hardness:** 66-69 HRC - **Retained Austenite:** <5% after proper treatment ### **Sub-Zero Treatment (Recommended)** - **Temperature:** -70 to -100°C (-95 to -150°F) - **Duration:** 2-4 hours - **Timing:** After quenching, before first temper - **Benefits:** Maximum hardness, dimensional stability - **Hardness Increase:** 0.5-1.5 HRC typical --- ## **5. Manufacturing & Processing** ### **Machinability (Annealed)** - **Relative Machinability:** 35-45% (1% carbon steel = 100%) - **Tool Requirements:** Carbide tools essential - **Cutting Parameters:** - Turning: 20-30 m/min (65-100 SFM) with carbide - Milling: 15-22 m/min (50-72 SFM) with carbide - Drilling: 8-12 m/min (25-40 SFM) with carbide - **Coolant:** Heavy-duty soluble oil or synthetic ### **Grinding Operations** - **Wheel Selection:** Aluminum oxide A46-J8-V or premium grades - **Parameters:** - Wheel Speed: 25-30 m/s (5000-6000 SFPM) - Infeed: 0.005-0.015 mm/pass - Crossfeed: 1-3 mm/pass - Spark-out: 2-3 passes recommended - **Coolant:** High-volume water-based synthetic - **Dressing:** Frequent dressing for optimal results ### **Quality Grades Available** | Grade Type | Description | Applications | |------------|-------------|--------------| | **Standard M42** | Conventional melting | General premium applications | | **Premium M42** | Special processing | Critical aerospace/medical | | **PM M42** | Powder metallurgy | Superior consistency, grindability | | **Surface Enhanced** | Special treatments | Maximum performance tools | --- ## **6. Comparative Analysis** ### **vs. Other Premium HSS Grades** | Property | M42 | M35 | M7 | T15 | |----------|-----|-----|----|-----| | **Cobalt Content** | 7.50-9.50% | 4.50-5.50% | 0% | 4.75-5.25% | | **Hot Hardness** | Excellent | Very Good | Good | Excellent | | **Room Temp Hardness** | 66-69 HRC | 65-67 HRC | 64-66 HRC | 66-68 HRC | | **Toughness** | Fair | Good | Very Good | Poor | | **Wear Resistance** | Good | Good | Very Good | Excellent | | **Grindability** | Good | Good | Very Good | Very Poor | | **Cost Factor** | 2.0-2.5x | 1.4-1.6x | 1.1-1.2x | 2.5-3.0x | ### **Performance/Cost Positioning** | Application | M42 Performance | Cost Efficiency | Best For | |-------------|-----------------|-----------------|----------| | **High-temp superalloys** | Excellent | Very Good | Most demanding high-temp applications | | **Titanium machining** | Very Good | Good | Production titanium operations | | **Hardened steel** | Good | Fair | Up to 55 HRC materials | | **General premium** | Excellent | Best | Broad range of difficult materials | | **High-speed operations** | Very Good | Good | Elevated speed requirements | ### **Market Position Analysis** - **Market Share:** ~25% of premium HSS market - **Growth Trend:** Stable, with migration to PM versions - **Primary Competition:** PM HSS, advanced carbide grades - **Future Outlook:** Continued strong position in specific applications --- ## **7. Surface Treatments & Coatings** ### **Recommended Coatings** 1. **TiAlN (Aluminum Titanium Nitride):** - Maximum temperature: 800°C - Color: Violet/black - Best for: High-temperature alloys, dry machining 2. **AlTiN (with higher Al content):** - Better oxidation resistance than TiAlN - Excellent for: Stainless steels, interrupted cuts 3. **TiSiN (Titanium Silicon Nitride):** - Nanocomposite structure - Superior for: Hard materials, high-speed machining ### **Coating Performance Data** - **Tool Life Improvement:** 3-6x uncoated life - **Cutting Speed Increase:** 30-60% possible - **Surface Finish Improvement:** 1-2 roughness grades - **Temperature Reduction:** 100-200°C at cutting edge ### **Pre-coating Requirements** - **Surface Finish:** <0.4 μm Ra optimal - **Edge Preparation:** Honed edges (0.03-0.08mm radius) - **Cleaning:** Ultrasonic cleaning essential - **Stress State:** Compressive surface stress preferred --- ## **8. Technical Recommendations** ### **Selection Guidelines** **Choose M42 when:** - Operating temperatures regularly exceed 500°C - M35 performance is insufficient - Maximum conventional HSS performance is required - Good grindability must be maintained - Production volumes justify premium cost **Consider alternatives when:** - Maximum wear resistance needed (M4 or high-vanadium grades) - Extreme abrasion conditions exist (specialized grades) - Maximum toughness required (lower cobalt grades) - Cost is primary driver (M35 or M2) - Powder metallurgy benefits needed (PM HSS) ### **Application Engineering** 1. **Parameter Optimization:** - Start at M35 parameters, increase speed 20-30% - Monitor tool temperature and wear - Optimize coolant delivery and type 2. **Tool Design Considerations:** - Adequate core strength for reduced toughness - Optimized flute design for chip evacuation - Proper edge preparation and honing 3. **Process Integration:** - Machine rigidity assessment - Workholding optimization - Coolant system evaluation ### **Economic Considerations** - **Break-Even Analysis:** Calculate based on tool life improvement - **Total Cost of Ownership:** Include regrinding, downtime, quality - **ROI Period:** Typically 6-18 months in production - **Inventory Strategy:** Balance availability vs. carrying cost ### **Common Issues & Solutions** | Problem | Root Causes | Preventive Actions | |---------|-------------|-------------------| | **Premature Flank Wear** | Insufficient hardness, coating | Verify heat treatment, apply appropriate coating | | **Edge Chipping** | Excessive feed, poor edge prep | Reduce feed, improve edge honing (0.05mm radius) | | **Thermal Cracking** | Heat concentration, poor cooling | Improve coolant delivery, reduce speed | | **Catastrophic Failure** | Overload, vibration, deflection | Improve rigidity, reduce cutting forces | | **Inconsistent Performance** | Heat treatment variations | Implement strict process control | --- ## **Disclaimer** This technical datasheet provides comprehensive information about AISI Type M42 high-speed tool steel based on industry standards, technical literature, and extensive application experience. Actual performance may vary depending on: **Critical Performance Factors:** 1. **Material Quality:** Manufacturer's processes and quality control 2. **Heat Treatment:** Precision of temperature control and quenching 3. **Tool Design:** Geometry, edge preparation, structural integrity 4. **Application Conditions:** Workpiece material, machine condition, coolant effectiveness 5. **Operating Parameters:** Optimization for specific conditions **Important Usage Guidelines:** - M42 represents the premium standard for high-performance HSS applications - Proper application engineering is essential for success - Performance should be validated under actual production conditions - Regular maintenance and monitoring maximize tool life and performance **Reference Standards:** - ASTM A600: Standard Specification for Tool Steel High Speed - ISO 4957: Tool steels - AMS 6390: Aerospace material specification - Manufacturer's technical data and processing guidelines This information represents current industry knowledge and best practices. Technology and standards evolve continuously, so users should: - Verify specifications with materials suppliers - Conduct application-specific testing for critical applications - Consult with technical specialists for unique requirements - Stay informed about developments in tool materials and coatings Always prioritize safety in all aspects of tool handling, operation, and maintenance, adhering to all applicable industry standards and regulations. -:- For detailed product information, please contact sales. -: AISI Type M42 Molybdenum High Speed Tool Steel (UNS T11342) Specification Dimensions Size： Diameter 20-1000 mm Length <6728 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 Type M42 Molybdenum High Speed Tool Steel (UNS T11342) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342) -:- For detailed product information, please contact sales. -:

Packing of AISI Type M42 Molybdenum High Speed Tool Steel Wire (UNS T11342) -:- 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 3199 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