1.2581 Tool Steel Flat Bar (Premium High-Performance Hot Work Die Steel)

Product Description

FUSHUN METAL's 1.2581 Tool Steel Flat Bar is a premium high-performance hot work die steel offering an exceptional combination of superior thermal fatigue resistance, outstanding toughness, excellent hot hardness, and remarkable wear resistance. With a carefully engineered chemical composition featuring a balanced ratio of tungsten, molybdenum, chromium, and vanadium, our 1.2581 flat bar delivers extraordinary performance in the most demanding hot working applications. Available in precision-milled finishes and tight dimensional tolerances, this specialized flat steel bar is ideal for challenging applications in hot forging dies, hot extrusion tooling, aluminum die casting, and other operations requiring exceptional resistance to thermal cracking, plastic deformation, and premature wear at elevated temperatures up to 600°C (1110°F). Unlike standard hot work steels, FUSHUN METAL's 1.2581 flat bars provide significantly enhanced resistance to thermal fatigue combined with superior toughness and wear resistance, ensuring extended tool life and reliable performance in severe thermal cycling applications. Each bar undergoes comprehensive quality control to ensure consistent properties, precise dimensions, and superior surface quality for maximum performance in critical hot work tooling applications.

Flat Bar Specifications

FUSHUN METAL offers 1.2581 Tool Steel Flat Bar in a comprehensive range of specifications to meet diverse application requirements:

Available Dimensions

* Custom dimensions available upon request

Dimensional Tolerances

Surface Finishes

• Hot Rolled: Standard industrial finish
• Hot Rolled and Annealed: Stress relieved for better machinability
• Hot Rolled, Annealed, and Pickled: Clean scale-free surface
• Precision Ground: Four sides ground with precision tolerances
• Fine Milled: High-quality surface finish with tight tolerances
• Polished: Smoother finish for reduced post-processing requirements
• Custom Finishes: Available upon request for specific applications

Supply Conditions

• Annealed: Soft condition for optimal machinability (190-240 HB)
• Pre-hardened: Hardened and tempered to 35-42 HRC for applications requiring moderate hardness
• Fully Heat Treated: Hardened and tempered to 44-52 HRC for immediate use
• Custom Heat Treatment: Available to meet specific hardness and toughness requirements

Packaging Options

• Individual Plastic Wrapping: For protection against environmental contaminants
• Wooden Crates: For secure shipping of multiple bars
• Steel Strapped Bundles: For economical shipping of standard orders
• VCI Paper Wrapping: For enhanced corrosion protection
• Oil Coating: Available for additional corrosion protection
• Custom Packaging: Available to meet specific handling and storage requirements
• Heavy-Duty Packaging: Specialized options for large sections and export shipments

Applications

FUSHUN METAL's 1.2581 Tool Steel Flat Bar is specifically engineered for applications requiring an optimal combination of thermal fatigue resistance, toughness, hot hardness, and wear resistance:

Hot Forging Applications

• Heavy-duty hot forging dies
• Hot heading tools for demanding applications
• Hammer forging dies subject to severe thermal cycling
• Press forging tooling for high-temperature operations
• Hot upset forging dies
• Forging mandrels and punches
• Hot trim dies for forged components
• Tooling for isothermal forging processes

Die Casting Applications

• Critical components in aluminum die casting tools
• Inserts and cores for high-pressure die casting
• Die casting dies for complex geometries
• Sprue bushings and shot sleeves
• Core pins for die casting dies
• Die components exposed to severe thermal fatigue
• Pressure blocks and ejector pins
• Tooling for magnesium die casting

Extrusion Applications

• Hot extrusion dies for aluminum profiles
• Container liners for extrusion presses
• Extrusion tooling for non-ferrous metals
• Mandrels for tube extrusion
• Dummy blocks for aluminum extrusion
• Stems and rams for extrusion equipment
• Dies for complex extrusion profiles
• Tooling components subject to severe wear and heat

Hot Stamping and Press Hardening

• Hot stamping dies for high-strength automotive parts
• Press hardening tools for advanced high-strength steels
• Hot forming punches and dies
• Hot shearing and trimming tools
• Progressive hot forming dies
• Hot piercing tools
• Thermal forming tooling for complex geometries
• Hot calibration tooling

Specialty Applications

• Hot shear blades for cutting at elevated temperatures
• Tooling for powder metallurgy hot compaction
• Hot work punches for severe applications
• Mandrels for seamless tube production
• Tooling for glass molding operations
• Hot working tools requiring exceptional thermal fatigue resistance
• Components exposed to cyclic heating and cooling
• Critical tooling with combined thermal and mechanical stress

Chemical Composition

FUSHUN METAL's 1.2581 Tool Steel Flat Bar features the following nominal composition per DIN 17350/EN ISO 4957 standards:

Key Element Functions

• Carbon (0.32-0.40%): Provides optimal hardness and strength while maintaining good toughness. The moderate carbon content offers an excellent balance between wear resistance and thermal shock resistance.
• Chromium (5.00-5.50%): Enhances hardenability, wear resistance, and oxidation resistance at elevated temperatures. Forms stable carbides that maintain hardness at high operating temperatures.
• Tungsten (1.00-1.50%): A key differentiating element in 1.2581 that provides exceptional hot hardness and resistance to softening at elevated temperatures. Tungsten contributes significantly to the steel's "red hardness" and thermal stability.
• Molybdenum (1.00-1.50%): Works synergistically with tungsten to enhance hot strength, creep resistance, and resistance to thermal fatigue. Improves hardenability and contributes to secondary hardening during tempering.
• Vanadium (0.30-0.50%): Forms fine, hard carbides that provide resistance to wear and abrasion. Refines grain structure for improved toughness and contributes to secondary hardening during tempering.
• Silicon (0.20-0.50%): Improves oxidation resistance and high-temperature strength. Contributes to overall toughness of the steel.
• Manganese (0.20-0.50%): Enhances hardenability and contributes to strength.
• Nickel (≤ 0.35%): Improves toughness and contributes to hardenability.

Physical and Mechanical Properties

Our 1.2581 Tool Steel Flat Bar offers an impressive combination of physical and mechanical properties that make it ideal for demanding hot work applications:

Physical Properties

Mechanical Properties (Annealed Condition)

Mechanical Properties (Hardened and Tempered to 45 HRC)

Mechanical Properties (Hardened and Tempered to 50 HRC)

Hot Hardness

1.2581 maintains excellent hardness at elevated temperatures, which is crucial for hot work applications:

Special Features of FUSHUN METAL's 1.2581 Tool Steel Flat Bar

Our 1.2581 Tool Steel Flat Bar offers several distinctive advantages that set it apart from conventional hot work tool steel products:

Superior Thermal Fatigue Resistance

1.2581 provides exceptional performance in applications with severe thermal cycling:

• Outstanding Resistance to Heat Checking: The unique combination of tungsten and molybdenum provides superior resistance to thermal fatigue cracking, significantly extending tool life in applications with repeated heating and cooling cycles.
• Excellent Thermal Shock Resistance: Superior resistance to cracking when subjected to rapid temperature changes, critical for processes with frequent heating and cooling.
• Enhanced Thermal Stability: Maintains dimensional stability during thermal cycling, ensuring consistent part quality throughout tool life.
• Reduced Propensity for Cracking: The balanced composition provides excellent resistance to crack initiation and propagation under thermal stress.
• Homogeneous Heat Distribution: Good thermal conductivity for a high-alloy tool steel, promoting more uniform heating and cooling.
• Controlled Thermal Expansion: Moderate thermal expansion coefficient reduces internal stresses during temperature changes.
• Extended Service Life: Significantly longer service life in applications where thermal fatigue is the primary failure mechanism.

Exceptional Hot Work Performance

1.2581 delivers remarkable performance at elevated temperatures:

• Superior Hot Hardness: The tungsten content provides exceptional retention of hardness at elevated temperatures up to 600°C (1110°F), outperforming standard hot work steels.
• High Temperature Strength: Maintains strength and resistance to plastic deformation at elevated operating temperatures.
• Excellent Wear Resistance at High Temperatures: Stable carbides provide good resistance to abrasive and adhesive wear even at elevated temperatures.
• Oxidation Resistance: Good resistance to scaling and oxidation at elevated temperatures due to chromium content.
• Tempering Resistance: Excellent resistance to softening during prolonged exposure to high temperatures.
• Consistent Performance: Maintains mechanical properties over a wide temperature range, providing reliable performance.
• Lower Tool Maintenance: Reduced frequency of maintenance and rework due to enhanced hot work performance.

Balanced Mechanical Properties

1.2581 offers an excellent combination of properties for demanding hot work applications:

• Excellent Toughness-Hardness Balance: Superior combination of toughness and hardness compared to many hot work tool steels, reducing the risk of premature failure in demanding applications.
• Good Machinability: Despite its high alloy content, maintains reasonable machinability in the annealed condition.
• Good Polishability: Can be polished to a high finish, important for die casting and extrusion applications.
• Weldability: Can be welded with proper precautions, allowing for repairs and modifications.
• Dimensional Stability: Good dimensional stability during heat treatment when properly processed.
• Uniform Properties: Consistent properties throughout the cross-section, even in larger sections.
• Good Grinding Characteristics: Responds well to precision grinding operations for finishing complex geometries.

Heat Treatment Response

1.2581 offers predictable and favorable response to heat treatment:

• Excellent Hardenability: Deep hardening capability in sections up to 150mm with appropriate quenching, ensuring uniform properties throughout.
• Secondary Hardening: Pronounced secondary hardening effect during tempering, contributing to excellent hot hardness.
• Wide Hardening Range: Can be hardened to various hardness levels (40-52 HRC) to optimize the balance between wear resistance and toughness for specific applications.
• Good Dimensional Control: Minimal distortion during heat treatment when properly processed.
• Double Tempering Response: Responds well to double or triple tempering for optimal property development.
• Predictable Size Change: Undergoes minimal and predictable dimensional changes during proper heat treatment.
• Air Hardening Capability: Can be air hardened in smaller sections, reducing distortion compared to oil quenching.

Manufacturing Excellence

FUSHUN METAL employs specialized processes to ensure our 1.2581 flat bars deliver reliable performance in critical applications:

• Premium Melting Processes: Vacuum degassed or electroslag remelted options available for enhanced cleanliness and performance in critical applications.
• Precise Chemical Control: Tight control of alloying elements, particularly tungsten and molybdenum, to ensure consistent heat treatment response and mechanical properties.
• Controlled Forging: Optimized forging practices to ensure homogeneous microstructure and uniform carbide distribution.
• Optimized Annealing: Precise annealing cycles to achieve uniform hardness and excellent machinability.
• Stress Relieving: Proper stress relief treatments to minimize distortion during machining and subsequent heat treatment.
• Precision Milling: Advanced milling capabilities to achieve tight dimensional tolerances and excellent surface finish.
• Rigorous Inspection: Comprehensive non-destructive testing to ensure internal quality and surface integrity.
• Carbide Evaluation: Microstructural examination to verify proper carbide size, type, and distribution.

Heat Treatment Recommendations

For customers performing their own heat treatment of 1.2581 tool steel flat bar, FUSHUN METAL recommends the following parameters:

Stress Relieving

• Heat slowly to 650-700°C (1200-1290°F)
• Hold for minimum 2 hours per 25mm of thickness
• Cool slowly in furnace to below 500°C (930°F), then air cool
• Recommended before extensive machining to minimize distortion

Annealing

• Heat slowly to 820-850°C (1510-1560°F)
• Hold for 1-2 hours per 25mm of thickness
• Cool slowly in furnace at a rate not exceeding 15°C (27°F) per hour to 600°C (1110°F)
• Continue cooling in furnace or air
• Resulting hardness: 190-240 HB

Hardening

• Preheating: Step 1: 650-750°C (1200-1380°F)
• Preheating: Step 2: 850-950°C (1560-1740°F)
• Austenitizing: 1000-1050°C (1830-1920°F)
  • Lower temperatures for better toughness, higher temperatures for maximum wear resistance
• Holding time: 20-45 minutes after thorough heating (minimum 30 minutes for sections over 50mm)
• Quenching: Oil, warm bath at 500-550°C (930-1020°F), or positive pressure gas quenching
• For complex shapes, martempering in salt bath is recommended to minimize distortion
• Air cooling possible for sections under 20mm
• Achievable hardness after quenching: 52-56 HRC

Tempering

• Temper immediately after cooling to hand-warm temperature (50-70°C/120-160°F)
• Tempering temperature selection based on desired final hardness:
  • 550-580°C (1020-1075°F): 44-48 HRC (balanced wear resistance and toughness)
  • 580-620°C (1075-1150°F): 40-44 HRC (maximum toughness for heavy duty applications)
  • 520-550°C (970-1020°F): 48-50 HRC (increased wear resistance for less severe applications)
  • 470-520°C (880-970°F): 50-52 HRC (maximum hardness, but reduced toughness)
• Hold at temperature for minimum 2 hours (1 hour per 25mm thickness recommended)
• Triple tempering recommended (minimum two tempers)
• Cool to room temperature between tempering cycles

Nitriding

• For enhanced surface hardness and wear resistance, 1.2581 responds well to nitriding
• Perform after final heat treatment and tempering at minimum 540°C (1000°F)
• Gas nitriding: 500-520°C (930-970°F) for 10-30 hours
• Plasma nitriding: 480-520°C (895-970°F) for 4-12 hours
• Salt bath nitriding: 540-560°C (1000-1040°F) for 2-4 hours
• Achievable surface hardness: 950-1100 HV (68-70 HRC)
• Typical case depth: 0.1-0.3 mm

Quality Assurance and Testing

Every batch of FUSHUN METAL's 1.2581 Tool Steel Flat Bar undergoes rigorous testing to ensure it meets our exacting quality standards:

• Chemical Composition Analysis: Spectrographic testing to verify precise element content critical for performance, with special attention to tungsten, molybdenum, chromium, and vanadium levels.
• Mechanical Property Testing: Hardness testing to confirm proper annealing or heat treatment.
• Microstructural Examination: Metallographic analysis to verify proper structure, grain size, and carbide distribution.
• Ultrasonic Testing: 100% ultrasonic inspection available to detect internal defects and ensure soundness.
• Magnetic Particle Inspection: Available to detect surface or near-surface defects.
• Dimensional Verification: Precision measurement to ensure tight dimensional tolerances.
• Flatness Testing: Verification of flatness to ensure minimal warpage.
• Heat Treatment Response Verification: Sample testing to confirm proper response to hardening and tempering.
• Hot Hardness Testing: Available to verify performance at elevated temperatures.
• Hardenability Testing: Jominy end-quench testing available upon request.
• Inclusion Assessment: Evaluation of non-metallic inclusion content for critical applications.
• Carbide Distribution Analysis: Examination of carbide type, size, and distribution for performance-critical applications.
• Thermal Fatigue Testing: Specialized testing available for critical applications to validate thermal fatigue resistance.

Certifications Provided

• Material Test Certificates according to EN 10204 3.1
• Chemical composition analysis
• Mechanical property test results
• Dimensional inspection report
• Heat treatment certification when applicable
• Special property verifications available upon request
• Certificate of conformity to ordered specifications
• Ultrasonic testing reports when specified
• Metallographic examination reports when specified

International Standards Compliance

Our 1.2581 Tool Steel Flat Bar complies with the following international standards:

Machining Recommendations

To achieve optimal results when machining 1.2581 tool steel flat bars, FUSHUN METAL recommends the following parameters:

Annealed Condition (190-240 HB)

Hardened and Tempered Condition (44-48 HRC)

* These values are guidelines only; adjustments may be necessary based on specific equipment and conditions

Machining Tips

• Use rigid setups with minimum overhang to minimize vibration and chatter.
• Apply adequate cooling, especially when machining in hardened condition.
• For complex geometries, consider machining in the annealed condition and then heat treating.
• Use sharp tools and replace at regular intervals to maintain dimensional accuracy.
• After EDM processing, remove the affected layer by grinding or polishing to ensure maximum tool performance.
• After heavy machining, consider stress relieving to minimize distortion during final heat treatment.
• When grinding hardened material, use gentle cutting conditions and adequate cooling to prevent rehardening of the surface.
• The tungsten and molybdenum content in 1.2581 causes increased tool wear compared to standard hot work steels; adjust tooling selection and cutting parameters accordingly.
• Consider using TiAlN or AlCrN coated carbide tools for improved tool life when machining 1.2581.
• When performing finish machining, make multiple light passes rather than a single heavy cut to maintain dimensional accuracy.

Welding Recommendations

1.2581 can be welded with proper precautions and procedures, though more care is required than with standard hot work steels due to its higher alloy content:

• Preheat: 300-400°C (570-750°F) depending on section thickness
• Filler Material: Matching composition or AWS A5.14 ERNiCrMo-3
• Process: TIG/GTAW strongly preferred for highest quality; MMA/SMAW also suitable with low hydrogen electrodes
• Interpass Temperature: Maintain 300-400°C (570-750°F)
• Post-weld Heat Treatment: Cool slowly to 100°C (212°F), then temper immediately at a temperature 25-50°C (45-90°F) below the previous tempering temperature
• Hydrogen Control: Use low hydrogen processes and consumables; bake electrodes according to manufacturer recommendations
• Joint Design: Use simple joint designs with adequate access; avoid sharp corners
• Special Consideration: Due to high tungsten and molybdenum content, 1.2581 requires careful welding procedures and is more susceptible to cracking than standard hot work steels
• Pre-weld Stress Relief: For repair welding of tools in service, a stress relief treatment is recommended before welding

Comparative Advantages over Other Tool Steel Grades

Understanding how 1.2581 tool steel flat bar compares to other grades helps in selecting the optimal material for your application:

Application-Specific Recommendations

FUSHUN METAL provides tailored recommendations for specific applications of 1.2581 tool steel flat bar:

Hot Forging Applications

• Recommended hardness: 44-46 HRC for heavy duty forging, 46-48 HRC for precision forging
• Ideal for dies subject to extreme thermal fatigue conditions
• Ensure adequate corner and fillet radii to minimize stress concentration (minimum 3mm)
• Preheat dies to 200-300°C (390-570°F) before use for increased thermal fatigue resistance
• Design proper cooling channels for temperature control during operation
• Triple tempering strongly recommended for maximum dimensional stability
• Consider nitriding for applications with severe sliding wear
• For high-volume production, implement proper cooling between forging cycles
• Regular inspection for heat checking recommended to prevent catastrophic failure

Die Casting Applications

• Recommended hardness: 44-46 HRC for aluminum, 42-44 HRC for zinc, 46-48 HRC for magnesium
• Ideal for components subjected to severe thermal cycling
• Design with adequate cooling channels to minimize thermal gradients
• Polish in the direction of material flow to optimize release
• Consider nitriding for enhanced surface durability and better release properties
• For critical components, perform stress relieving after rough machining and before final heat treatment
• Proper preheating and cooling of the die essential for maximum life
• PVD coating can significantly extend die life in high-pressure applications
• Regular maintenance including polishing and inspection for heat checking recommended

Extrusion Applications

• Recommended hardness: 46-48 HRC for aluminum extrusion, 44-46 HRC for copper/brass extrusion
• Particularly suitable for extrusion dies with complex geometries
• Consider nitriding for dies and components subject to severe abrasive wear
• Proper preheating of tooling before use is essential to minimize thermal shock
• Highly polished die surfaces recommended for improved material flow
• For severe applications, stress relieve after rough machining before final heat treatment
• Consider PVD coating for extended die life in abrasive applications
• Implement proper cooling between extrusion cycles to minimize thermal fatigue
• Regular maintenance including polishing and inspection recommended for maximum tool life

Customization Capabilities

FUSHUN METAL offers extensive customization options to meet your specific application requirements:

• Custom Dimensions: Special sizes manufactured to exact specifications for your application.
• Modified Chemical Composition: Slight adjustments to standard composition available to optimize specific properties.
• Special Melting Routes: Vacuum degassed or electroslag remelted material available for critical applications requiring enhanced cleanliness.
• Pre-Machining Services: Basic machining including cutting to length, face milling, drilling, and tapping available.
• Heat Treatment Services: Custom heat treatment to achieve specific hardness and toughness combinations.
• Surface Treatments: Nitriding, PVD coating, and other treatments available upon request.
• Specialized Testing: Application-specific testing protocols available upon request.
• Custom Packaging: Specialized packaging for long-term storage or export shipments.
• Edge Preparation: Chamfering and deburring of edges for safe handling.
• Technical Consultation: Expert metallurgical support for your specific application challenges.
• Material Certification: Enhanced certification packages for critical applications.
• Rough Machining: Pre-machined blocks available to reduce your processing time.
• Thermal Fatigue Testing: Specialized testing for critical applications to validate thermal fatigue resistance.

Why Choose FUSHUN METAL for 1.2581 Tool Steel Flat Bar

When you select FUSHUN METAL as your supplier for 1.2581 Tool Steel Flat Bar, you partner with a leading manufacturer committed to excellence:

• Specialized Tool Steel Expertise: Extensive experience in manufacturing premium tungsten-containing hot work tool steel products with optimal properties.
• Advanced Production Facilities: State-of-the-art melting, forging, and processing equipment specifically optimized for specialty tool steels.
• Stringent Quality Control: Comprehensive testing and inspection protocols ensure consistent performance in demanding applications.
• Metallurgical Knowledge: In-depth understanding of heat treatment and microstructural control of complex hot work tool steels.
• Supply Chain Reliability: Robust inventory management and production planning to ensure consistent availability of critical materials.
• Technical Support: Expert assistance in material selection, heat treatment guidance, and application support.
• Global Capabilities: Worldwide shipping network with experience in international documentation and compliance.
• Material Traceability: Complete documentation and batch traceability for quality assurance.
• Continuous Improvement: Ongoing research and development in tool steel processing and performance.
• Industry Compliance: Materials and processes that meet or exceed international standards for critical applications.
• Competitive Pricing: Excellent value combined with superior quality and service.
• Environmental Responsibility: Commitment to sustainable manufacturing practices and environmental management.

Request Information

Contact FUSHUN METAL today to discuss your 1.2581 Tool Steel Flat Bar requirements. Our technical team is ready to assist you with:

• Detailed product specifications
• Technical consultations for your specific application
• Heat treatment recommendations for optimal properties
• Custom dimension and processing requirements
• Pricing inquiries and delivery schedules
• Sample requests for evaluation

FUSHUN METAL – Your trusted partner for premium hot work tool steel solutions that deliver consistent quality, superior thermal fatigue resistance, and exceptional hot work performance in the most demanding applications.