Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5)

Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) Product Information -:- For detailed product information, please contact sales. -: Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) Synonyms -:- For detailed product information, please contact sales. -:

Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM A681)** **Latrobe LSS™ S5** is a premium-grade, **silicon-molybdenum shock-resisting tool steel** specifically engineered to deliver exceptional impact toughness and fatigue resistance under severe dynamic loading conditions. Classified under ASTM A681 Grade S5, this specialized air-hardening steel combines high strength with remarkable shock absorption capabilities, making it the material of choice for applications subjected to repeated heavy impact, high stress concentrations, and demanding service environments. With its unique silicon-rich composition, S5 offers superior toughness retention at both room and elevated temperatures compared to conventional shock-resistant grades. The defining advantage of LSS™ S5 lies in its **exceptional combination of high toughness (impact strength) and good wear resistance** at hardness levels typically ranging from 54-58 HRC. Its air-hardening characteristic provides minimal distortion during heat treatment, making it suitable for complex tool geometries requiring dimensional stability under impact loading. --- ## **1. Chemical Composition** Latrobe LSS™ S5 features a specialized silicon-molybdenum alloy system optimized for maximum toughness: | Element | Content (%) | Function | | :--- | :--- | :--- | | Carbon (C) | 0.50 - 0.65 | Provides core hardness and strength | | Silicon (Si) | 1.75 - 2.25 | **Key element** - dramatically increases toughness and fatigue strength | | Molybdenum (Mo) | 0.30 - 0.60 | Enhances hardenability and tempering resistance | | Manganese (Mn) | 0.60 - 1.00 | Improves hardenability and strength | | Chromium (Cr) | 0.20 - 0.50 | Contributes to hardenability and wear resistance | | **Balance** | Iron (Fe) | | *(Composition conforms to ASTM A681 Grade S5 specifications. The high silicon content is distinctive to this grade.)* --- ## **2. Physical & Mechanical Properties** ### **Annealed Condition Properties:** - **Hardness:** 192 - 223 HB (Brinell) - **Machinability:** Fair to Good (rated 45% of 1% carbon steel standard) - **Density:** 7.83 g/cm³ (0.283 lb/in³) - **Modulus of Elasticity:** 205 GPa (29.7 × 10⁶ psi) - **Thermal Conductivity:** 36.5 W/m·K at 20°C - **Coefficient of Thermal Expansion:** 11.8 × 10⁻⁶/°C (20-100°C) ### **Heat Treatment Characteristics:** - **Hardening Method:** Air hardening (primary), can be oil quenched for maximum toughness - **Austenitizing Temperature:** 870°C - 900°C (1600°F - 1650°F) - **Preheating:** 650°C (1200°F) and 790°C (1450°F) recommended - **Quenching:** Still air or forced air circulation - **Tempering Range:** 205°C - 540°C (400°F - 1000°F) ### **Hardened & Tempered Properties:** - **Optimal Hardness Range:** **54 - 58 HRC** (for best toughness/strength balance) - **Charpy Impact Value (unnotched):** **85 - 120 J** (at 54-56 HRC) - **Exceptional** - **Transverse Rupture Strength:** 3,600 - 4,200 MPa - **Compressive Strength:** 2,100 - 2,500 MPa - **Fatigue Strength:** 1,100 - 1,300 MPa (rotating bending, 10⁷ cycles) - **Key Characteristics:** - **Superior Impact Toughness:** Highest among S-series steels - **Excellent Fatigue Resistance:** Ideal for cyclic loading applications - **Good Wear Resistance:** Better than S7 at equivalent hardness - **Minimal Distortion:** Air hardening ensures dimensional stability - **Deep Hardening:** Full hardness to 100mm (4") diameter in air --- ## **3. International Standards & Cross-Reference** | Country/Region | Standard | Designation | | :--- | :--- | :--- | | **United States** | ASTM A681 | Grade S5 | | | AISI | S5 | | | UNS | T41905 | | **Germany** | DIN 17350 | 1.2542 (similar, but different composition) | | **Japan** | JIS G4404 | - | | **United Kingdom** | BS 4659 | BS5 | | **Sweden** | SS 14 2140 | - | | **International** | ISO 4957 | 55SiMo8 (similar grade) | --- ## **4. Product Applications** ### **Primary Impact Applications:** - **Heavy-Duty Punching Tools:** For thick materials and high-tonnage presses - **Cold Chisels and Cutting Tools:** For metalworking and demolition - **Bolt Headers and Cold Forging Dies:** Subjected to extreme impact loads - **Shear Blades and Cutting Knives:** For structural steel and heavy plate - **Pneumatic Tool Components:** Jackhammer bits, rock drill steels ### **Specialized Industrial Tools:** - **Hot Work Tools:** For moderate temperature applications (up to 425°C/800°F) - **Crusher Parts and Hammer Mill Components:** In mining and aggregate industries - **Woodworking Tools:** Chipper knives, log splitter wedges - **Construction Equipment:** Pile driver components, breaker tools - **Railroad Tools:** Spike drivers, track maintenance tools ### **Precision Tooling:** - **Thread Rolling Dies:** For high-strength materials - **Forming Tools:** Subjected to intermittent heavy loads - **Die Inserts:** For high-impact forming operations - **Machine Components:** Bushings, wear plates in high-shock environments --- ## **5. Processing Guidelines** ### **Machining (Annealed State):** - **Turning Speed:** 20-30 m/min (65-100 ft/min) - **Feed Rate:** 0.15-0.25 mm/rev (0.006-0.010 in/rev) - **Tool Material:** Premium carbide or high-speed steel with positive rake angles - **Chip Control:** Produces continuous chips - use chip breakers - **Coolant:** Recommended to control heat and extend tool life ### **Heat Treatment Procedure:** 1. **Preheating:** 650°C (1200°F) for 30 min/inch, then 790°C (1450°F) for 20 min/inch 2. **Austenitizing:** 885°C (1625°F) for 20-30 minutes per inch of thickness 3. **Quenching:** Air cool in still air (for complex shapes) or forced air (for faster cooling) 4. **Tempering:** Immediately after reaching hand-warm temperature - For maximum toughness (54-56 HRC): 425°C - 480°C (800°F - 900°F) for 2+2 hours - For higher hardness (56-58 HRC): 315°C - 370°C (600°F - 700°F) for 2+2 hours ### **Special Heat Treatment Notes:** - **Deep Freezing:** Optional, not typically required due to air-hardening nature - **Multiple Tempering:** Highly recommended (double or triple tempering) - **Stress Relieving:** 650°C (1200°F) after rough machining, slow cool ### **Grinding:** - **Wheel Selection:** Aluminum oxide, medium hardness (J-L grade) - **Wheel Speed:** 25-28 m/s (5000-5500 SFPM) - **Coolant:** Essential - use abundant coolant to prevent overheating - **Technique:** Light, frequent passes with good wheel maintenance - **Surface Finish:** Can achieve good finishes with proper technique --- ## **6. Performance Comparison** ### **vs. S7 (Chromium-Molybdenum Shock Steel):** - **S5:** Higher toughness, better fatigue resistance, higher silicon content - **S7:** Better deep-hardening capability, slightly better dimensional stability - **Cost:** Comparable, with S5 often preferred for extreme impact applications ### **vs. L6 (Oil-Hardening Nickel Steel):** - **S5:** Higher hardness capability, better wear resistance, air-hardening - **L6:** Better machinability, slightly higher toughness at lower hardness - **Applications:** S5 for complex shapes requiring stability, L6 for simpler oil-hardened tools ### **vs. H13 (Hot Work Steel):** - **S5:** Superior room temperature impact strength - **H13:** Better hot hardness and thermal fatigue resistance above 425°C (800°F) - **Temperature Range:** S5 optimal for <425°C, H13 for higher temperatures --- ## **7. Technical Advantages** ### **Unique Properties:** 1. **Exceptional Toughness:** Highest impact strength in its hardness class 2. **Fatigue Resistance:** Excellent performance under cyclic loading conditions 3. **Stable Heat Treatment:** Minimal distortion due to air hardening 4. **Versatile Hardness Range:** Can be tempered from 50-60 HRC depending on needs ### **Economic Benefits:** - **Extended Tool Life:** 3-4 times longer than conventional tool steels in impact applications - **Reduced Downtime:** Less frequent tool changes and maintenance - **Safety Enhancement:** Reduced risk of catastrophic failure in demanding applications - **Versatility:** Suitable for both hot and cold impact applications --- ## **8. Special Applications & Considerations** ### **High-Stress Applications:** - **Cold Forging:** Excellent for high-impact forming operations - **Heavy Stamping:** Withstands extreme tonnage and intermittent loading - **Demolition Tools:** Resists chipping and breaking under unpredictable loads ### **Safety-Critical Components:** - **Tool Holders and Adapters:** Where failure could cause secondary damage - **Safety Equipment Components:** Requiring high impact absorption - **Industrial Machinery:** Critical parts subjected to shock loads ### **Design Considerations:** - **Section Size:** Full hardening in air to 100mm (4") diameter - **Geometry:** Avoid sharp corners and stress risers - **Support Design:** Ensure proper support to maximize tool life - **Maintenance Schedule:** Regular inspection for cracks and wear --- ## **9. Availability & Specifications** ### **Standard Forms:** - **Round Bars:** 10mm to 300mm diameter (0.375" to 12") - **Flat Stock:** 6mm to 150mm thickness (0.25" to 6") - **Square Bars:** 10mm to 150mm (0.375" to 6") - **Forged Blocks:** Custom sizes for tooling applications - **Plate:** Up to 300mm thick ### **Quality Standards:** - **Microcleanliness:** Controlled inclusion content for maximum toughness - **Homogeneity:** Uniform structure throughout cross-section - **Decarburization:** Controlled per ASTM specifications - **Surface Quality:** Suitable for precision tooling applications ### **Certifications:** - Mill test reports with full chemical analysis - Hardness certification throughout length - Ultrasonic testing available for critical applications - Full traceability to heat and lot numbers --- ## **10. Maintenance & Service Life Extension** ### **Preventive Maintenance:** - **Regular Inspection:** Check for cracks, spalling, and excessive wear - **Proper Sharpening:** Maintain optimal edge geometry and angles - **Corrosion Protection:** Apply protective coatings if used in corrosive environments - **Usage Monitoring:** Track service cycles and impact counts ### **Reconditioning Options:** - **Welding:** Possible with proper procedures (preheat to 315°C/600°F) - **Rehardening:** Can be re-heat treated if not overheaten in service - **Surface Treatments:** Nitriding or hard coating can extend wear life ### **Failure Analysis Support:** - **Common Failure Modes:** Fatigue cracking, abrasive wear, edge deformation - **Prevention Strategies:** Proper hardness selection, optimized geometry, correct application - **Technical Support:** Available for failure investigation and solution development --- **Technical Summary:** Latrobe LSS™ S5 represents the **pinnacle of impact toughness** in conventional tool steels, offering an exceptional balance of shock resistance, dimensional stability, and practical hardness. Its high silicon content provides unique benefits in fatigue resistance and toughness retention that distinguish it from other shock-resistant grades. While specialized in its application focus, S5 delivers unparalleled performance in environments where tools must withstand severe and repeated impact loading without compromising on dimensional accuracy or service life. **Industry Recognition:** S5 has earned a reputation as the "go-to" material for the most demanding impact applications across multiple industries, from heavy manufacturing to construction and mining. Its consistent performance in extreme conditions has made it a trusted choice for critical tooling. **Safety Emphasis:** For impact tools, proper heat treatment, regular inspection, and adherence to manufacturer guidelines are essential for safety. Always follow industry best practices and safety standards. **Disclaimer:** Performance data represents typical values from controlled conditions. For safety-critical applications, conduct thorough testing under actual service environments. Always consult Latrobe's current technical documentation and processing recommendations for specific application requirements. Material properties can vary based on processing history and service conditions. -:- For detailed product information, please contact sales. -: Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) Specification Dimensions Size： Diameter 20-1000 mm Length <7203 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. -: Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) Properties -:- For detailed product information, please contact sales. -:

Applications of Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) -:- For detailed product information, please contact sales. -: Chemical Identifiers Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) -:- For detailed product information, please contact sales. -:

Packing of Latrobe LSS™ S5 Shock-Resisting Tool Steel (ASTM S5) -:- 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 3674 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