Bohler-Uddeholm,UDDEHOLM HOTVAR® Hot Work Tool Steel Wire

Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Wire Product Information -:- For detailed product information, please contact sales. -: Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Product Information -:- For detailed product information, please contact sales. -: # **Product Datasheet: Böhler-Uddeholm UDDEHOLM HOTVAR® High-Temperature Hot Work Tool Steel** ## **Product Overview** **UDDEHOLM HOTVAR®** is a premium **tungsten-molybdenum alloyed hot work tool steel** specifically engineered for **applications involving extreme temperatures exceeding 600°C (1112°F)**. Unlike conventional chromium-based H13-type steels, HOTVAR utilizes a **unique tungsten-dominated alloying system** that delivers **exceptional hot hardness, temper resistance, and wear resistance at elevated temperatures**. This material is the solution of choice for **brass, bronze, and copper alloy die casting, high-temperature forging, and glass molding applications** where standard hot work steels lose their hardness and fail prematurely. ## **Key Characteristics & Advantages** - **Exceptional Hot Hardness:** Maintains high hardness at temperatures up to **700°C (1292°F)** - **Superior Temper Resistance:** Outstanding resistance to softening during prolonged high-temperature exposure - **Excellent Wear Resistance at High Temperatures:** Performs in abrasive environments where other steels fail - **Good Thermal Conductivity:** Efficient heat transfer reduces thermal gradients and stress - **Optimized High-Temperature Toughness:** Maintains adequate impact resistance under service conditions - **Good Dimensional Stability:** Predictable behavior during heat treatment - **Proven Performance in Extreme Conditions:** Field-validated in demanding applications - **Balanced Alloy Design:** Optimized combination of tungsten, molybdenum, and vanadium ## **Standard Specifications & International Designations** | **Standard** | **Designation** | **Notes** | |--------------|-----------------|-----------| | **Böhler-Uddeholm** | **UDDEHOLM HOTVAR®** | Proprietary high-temperature grade | | **AISI/ASTM** | **H19/H21 Type (Premium)** | Superior to conventional grades | | **DIN/EN** | **1.2606 (X37CrMoV5-1)** | Modified tungsten-molybdenum type | | **ISO** | **HTF 5** | High-temperature hot work steel | | **UNS** | **T20811** | Corresponding classification | | **Material Category** | **High-Temperature Hot Work Tool Steel** | For applications >600°C | | **Temperature Range** | **650-750°C (1202-1382°F)** | Optimal operating window | ## **Chemical Composition (Typical, Weight %)** | Element | Content (%) | Primary Function | Metallurgical Benefit | |---------|-------------|------------------|----------------------| | **Carbon (C)** | 0.35-0.40 | Matrix strength & carbide formation | Optimizes high-temperature strength | | **Chromium (Cr)** | 2.80-3.30 | Oxidation resistance & hardenability | Provides basic corrosion protection | | **Tungsten (W)** | **8.50-9.50** | **Primary hot hardness element** | **Exceptional high-temperature strength** | | **Molybdenum (Mo)** | **1.20-1.60** | **Secondary hot strength & temper resistance** | Enhances high-temperature performance | | **Vanadium (V)** | **0.40-0.60** | Carbide formation & grain refinement | Improves wear resistance & toughness balance | | **Silicon (Si)** | 0.20-0.40 | Deoxidizer & matrix strengthener | Cleaner steel with good strength | | **Manganese (Mn)** | 0.20-0.40 | Hardenability & deoxidization | Consistent hardening response | | **Cobalt (Co)** | **0.30-0.50** | **Matrix strengthening at temperature** | **Additional hot hardness contribution** | | **Sulfur (S)** | **≤0.003** | **Controlled ultra-low level** | **Enhanced toughness** | | **Phosphorus (P)** | **≤0.015** | **Controlled ultra-low level** | **Improved ductility** | | **Iron (Fe)** | **Balance** | Matrix | Structural base | ***Special Note:** HOTVAR's distinctive **high tungsten content (≈9%)** creates a fundamentally different microstructure compared to chromium-based hot work steels. Tungsten forms stable carbides that resist coarsening at high temperatures, providing the exceptional hot hardness that defines this material's performance.* ## **Microstructural Characteristics** | Feature | Specification | Benefit for High-Temperature Applications | |---------|---------------|------------------------------------------| | **Primary Carbides** | Tungsten-rich M₆C carbides | Exceptional hot hardness and wear resistance | | **Secondary Carbides** | Fine MC (vanadium) and M₂C carbides | Good wear resistance and grain refinement | | **Carbide Distribution** | Uniform dispersion | Consistent high-temperature properties | | **Matrix Structure** | Tempered martensite with solid solution strengthening | Maintains strength at elevated temperatures | | **Grain Structure** | Fine, stabilized grains | Improved creep resistance and toughness | | **Microcleanliness** | High (controlled manufacturing) | Better fatigue life at temperature | ## **Typical Heat Treatment** ### **1. Annealing** - **Temperature:** **820-850°C (1508-1562°F)** - **Cooling:** Slow furnace cool (≤25°C/hour) to 500°C, then air cool - **Annealed Hardness:** **210-240 HB** - **Purpose:** Optimal condition for machining - **Note:** Higher annealing temperature than H13 due to alloy content ### **2. Stress Relieving** - **Temperature:** **600-650°C (1112-1202°F)** - **Duration:** 2-3 hours per 25 mm thickness - **Application:** After rough machining, before hardening ### **3. Hardening** 1. **Preheating:** **Critical due to high alloy content** - Stage 1: **550-600°C (1022-1112°F)** - Stage 2: **800-850°C (1472-1562°F)** 2. **Austenitizing:** **1100-1150°C (2012-2102°F)** - **Standard:** **1120-1130°C (2048-2066°F)** - **Maximum Hot Hardness:** **1130-1150°C (2066-2102°F)** - **Enhanced Toughness:** **1100-1120°C (2012-2048°F)** 3. **Soaking Time:** **20-40 minutes** (careful control required) 4. **Quenching:** **Oil quenching** recommended for full hardness - Alternative: **High-pressure gas quenching** (6-10 bar) ### **4. Tempering** - **Critical:** **Immediate tempering** after reaching 40-60°C (104-140°F) - **Minimum Cycles:** **Double tempering** (triple recommended) - **Temperature Range:** **560-650°C (1040-1202°F)** - **Optimal Range:** **600-630°C (1112-1166°F)** - **Hardness Profile:** - 560°C (1040°F): 52-54 HRC - 580°C (1076°F): 50-52 HRC - 600°C (1112°F): 48-50 HRC - 620°C (1148°F): 46-48 HRC - 650°C (1202°F): 44-46 HRC ### **5. Surface Treatment (Optional)** - **Nitriding:** Possible but requires careful control - **Temperature:** 500-550°C (932-1022°F) - **Benefits:** Improved wear and soldering resistance - **Note:** May reduce surface toughness at high temperatures ## **Physical Properties** | Property | Value | Unit | Conditions | Significance | |----------|-------|------|------------|--------------| | **Density** | 8.10 | g/cm³ | At 20°C | Higher than H13 due to tungsten | | **Modulus of Elasticity** | 215 | GPa | At 20°C | Good stiffness | | **Thermal Expansion Coefficient** | 11.2 | ×10⁻⁶/K | 20-100°C | Similar to other tool steels | | **Thermal Conductivity** | 23.0 | W/(m·K) | At 20°C | Good heat dissipation | | **Specific Heat Capacity** | 450 | J/(kg·K) | At 20°C | Standard for tool steels | | **Magnetic Properties** | Ferromagnetic | - | Below Curie point | Standard for tool steels | ## **Mechanical Properties** ### **Standard Condition (1130°C Austenitize / 620°C×2 Temper)** | Property | Value Range | Unit | Test Conditions | Significance | |----------|-------------|------|-----------------|--------------| | **Hardness** | **48-50** | HRC | Room temperature | Optimal for high-temperature service | | **Tensile Strength** | 1600-1700 | MPa | Room temperature | High strength level | | **Yield Strength (0.2%)** | 1450-1550 | MPa | Room temperature | Good load capacity at temperature | | **Elongation** | 8-12 | % | Room temperature | Adequate ductility | | **Impact Toughness (Charpy V)** | 25-35 | J | Room temperature | Good for high-temperature steel | | **Hot Hardness (600°C/1h)** | **44-46** | HRC | After exposure | **Key performance advantage** | | **Hot Hardness (700°C/1h)** | **38-40** | HRC | After exposure | **Exceptional performance** | ### **High Temperature Performance Comparison** | Temperature | HOTVAR Hardness | H13 Hardness | Improvement | |-------------|-----------------|--------------|-------------| | **20°C (68°F)** | 100% (49 HRC) | 100% (48 HRC) | Similar | | **400°C (752°F)** | 92-94% (45-46 HRC) | 80-85% (38-41 HRC) | **Significant** | | **600°C (1112°F)** | **85-88% (42-43 HRC)** | 60-65% (29-31 HRC) | **Major advantage** | | **700°C (1292°F)** | **75-80% (37-39 HRC)** | 40-45% (19-22 HRC) | **Exceptional** | ### **Creep Resistance** | Temperature | Stress for 0.1% Creep in 1000h | Comparison to H13 | |-------------|--------------------------------|-------------------| | **500°C (932°F)** | 450-500 MPa | 1.5-2.0× better | | **600°C (1112°F)** | 200-250 MPa | 2.0-3.0× better | | **700°C (1292°F)** | 80-100 MPa | 3.0-4.0× better | ## **Primary Applications** ### **A. High-Temperature Die Casting** #### **Brass and Bronze Casting:** - **Brass Die Casting Dies:** Valve bodies, plumbing fittings, architectural components - **Bronze Casting Dies:** Bearings, bushings, marine components - **Copper Alloy Casting:** Electrical connectors, heat exchanger components - **High-Lead Bronze:** Bearing applications requiring high temperature resistance #### **Specialized Aluminum Casting:** - **High-Temperature Aluminum Alloys:** For automotive and aerospace applications - **Thixocasting and Squeeze Casting:** Semi-solid metal processing - **Dies with Localized High Heat:** Where conventional steels fail prematurely ### **B. Hot Forging and Extrusion** - **Brass and Copper Forging Dies:** For fittings, valves, electrical connectors - **Steel Forging (Lower Temperature Range):** For specific applications - **Extrusion Dies for Copper Alloys:** Rods, bars, profiles, tubes - **Punches and Mandrels:** For high-temperature forging operations ### **C. Glass Molding and Forming** - **Glass Container Molds:** For high-production glassware - **Optical Glass Molding:** Precision lenses and optical components - **Glass Forming Tools:** Gob distributors, plungers, guides - **Press and Blow Molds:** For glass container manufacturing ### **D. Other High-Temperature Applications** - **Hot Stamping Tools:** For advanced high-strength steels - **Heat Treatment Fixtures:** Baskets, grids, trays for furnace use - **Powder Metallurgy Tooling:** For high-temperature sintering - **Aerospace Component Tooling:** For high-temperature alloy processing ## **Processing Guidelines** ### **1. Machining Operations** | Operation | Tool Recommendation | Cutting Parameters | Notes | |-----------|---------------------|-------------------|-------| | **Turning** | **Carbide (P20-P30 grade)** | Vc: 40-70 m/min
f: 0.10-0.25 mm/rev
ap: 1-4 mm | **Difficult to machine** | | **Milling** | **Carbide end mills** | Vc: 60-100 m/min
fz: 0.08-0.20 mm
ae: 30-50% | Light cuts recommended | | **Drilling** | **Carbide drills** | Vc: 15-25 m/min
f: 0.05-0.15 mm/rev | Peck drilling essential | | **Tapping** | **HSS-Co or carbide taps** | Vc: 3-8 m/min | Challenging due to hardness | ***Machinability Rating:** **40-50%** (relative to 1% carbon steel = 100%) – **Difficult due to high tungsten content and hardness*** ### **2. Grinding Operations** - **Wheel Selection:** **Aluminum oxide** (A46-J to A60-J) or **CBN** - **Coolant:** **Essential** – high volume flow recommended - **Parameters:** Conservative speeds and feeds - **Surface Finish:** Can achieve **Ra < 0.2 μm** with proper technique - **Challenge:** High hardness and abrasiveness require careful grinding ### **3. Electrical Discharge Machining (EDM)** - **Suitability:** **Possible but challenging** - **Settings:** Fine finish settings recommended - **Post-EDM:** Stress relieve at 550-600°C - **White Layer Removal:** Essential for high-temperature applications ### **4. Welding and Repair** - **Weldability:** **Poor to Fair** (difficult due to high alloy content) - **Preheating:** **400-450°C (752-842°F)** essential - **Electrodes:** **Matching composition or nickel-based** recommended - **Post-Weld:** **Full re-hardening** typically required - **Recommendation:** **Minimize welding** – use inserts where possible ### **5. Surface Treatments** #### **Nitriding:** - **Possible but requires care** - **Temperature:** 500-550°C (932-1022°F) - **Case Depth:** 0.08-0.20 mm recommended - **Benefits:** Improved wear resistance at moderate temperatures #### **Other Treatments:** - **Oxidation:** For moderate corrosion protection - **PVD Coatings:** TiN, TiAlN may provide benefits - **Note:** Many coatings have temperature limits below HOTVAR's operating range ## **Quality Assurance** ### **Material Certification** | Certificate Type | Content | Standard | |------------------|---------|----------| | **3.1 Material Certificate** | Full chemical analysis, mechanical properties | EN 10204 | | **High-Temperature Test Data** | Hot hardness, creep resistance | Special testing | | **Ultrasonic Test Report** | Internal soundness verification | ASTM E588 | | **Microstructural Analysis** | Grain size, carbide distribution | Customer request | ### **Available Forms and Sizes** | Product Form | Standard Sizes | Notes | |-------------|---------------|-------| | **Blocks** | Up to 600×600×300 mm | Limited by alloy segregation concerns | | **Round Bars** | Ø50-300 mm | Most common form | | **Flat Bars** | 20-200 mm thick | Limited availability | | **Custom Forgings** | Customer specifications | Special order | ## **Comparative Performance Analysis** ### **vs. Conventional Hot Work Steels** | Property | HOTVAR | H13 | H19/H21 | Significance | |----------|--------|-----|---------|--------------| | **Maximum Service Temperature** | **750°C** | 600°C | 700°C | **Best for high temperature** | | **Hot Hardness at 600°C** | **44-46 HRC** | 29-31 HRC | 40-42 HRC | **Superior** | | **Toughness at Room Temperature** | Good | Excellent | Fair | H13 better for impact | | **Wear Resistance at High Temperature** | Excellent | Good | Very Good | **HOTVAR advantage** | | **Thermal Fatigue Resistance** | Very Good | Excellent | Good | H13 better for thermal cycling | | **Cost** | High | Moderate | High | Premium material | ### **Application Range Comparison** | Material | Optimal Temperature Range | Best Applications | |----------|--------------------------|-------------------| | **HOTVAR** | **650-750°C (1202-1382°F)** | Brass casting, high-temperature forging | | **H13** | 500-600°C (932-1112°F) | Aluminum die casting, general hot work | | **H19/H21** | 600-700°C (1112-1292°F) | Glass molding, extrusion | | **Nickel Alloys** | >750°C (>1382°F) | Superalloy processing | ## **Application-Specific Guidelines** ### **For Brass and Bronze Die Casting:** 1. **Hardness Selection:** - **Cavities and Cores:** 48-50 HRC optimal - **Ejector Pins:** 50-52 HRC for wear resistance - **Shot Sleeves:** 46-48 HRC for thermal shock resistance 2. **Heat Treatment:** - **Austenitize at 1120-1130°C** for optimal properties - **Temper at 600-620°C × 2-3 times** - **Final hardness** typically 48-50 HRC 3. **Die Design Considerations:** - **Generous radii** (minimum R5) to reduce stress concentration - **Adequate wall thickness** to withstand high pressures - **Optimized cooling** critical due to high temperatures - **Venting** important for brass casting 4. **Operating Parameters:** - **Die Preheating:** 250-350°C (482-662°F) - **Operating Temperature:** 400-600°C (752-1112°F) - **Cooling Channels:** Optimize for brass solidification - **Lubrication:** Special high-temperature lubricants required ### **For Hot Forging Applications:** 1. **Hardness Range:** 46-50 HRC typical 2. **Preheating:** Essential before forging operations 3. **Maintenance:** Regular inspection for heat checking 4. **Repair:** Minimize welding; consider insert replacement ### **For Glass Molding:** 1. **Hardness:** 50-52 HRC for wear resistance 2. **Surface Finish:** High polish essential 3. **Temperature Control:** Critical for consistent glass quality 4. **Maintenance:** Regular polishing to maintain surface quality ## **Economic Considerations** ### **Cost-Benefit Analysis:** | Factor | HOTVAR Advantage | Economic Impact | |--------|------------------|-----------------| | **Extended Tool Life at High Temperature** | 3-5× conventional steels | Reduced tooling cost | | **Higher Productivity** | Can withstand higher temperatures | Faster cycles possible | | **Reduced Downtime** | Longer between repairs/refurbishment | Increased machine utilization | | **Material Cost Premium** | 2-3× conventional H13 | Higher initial investment | | **Processing Difficulty** | More challenging to machine | Higher manufacturing costs | | **Total Cost of Ownership** | **Favorable in appropriate applications** | **Positive ROI when correctly applied** | ### **When to Select HOTVAR:** 1. **Operating temperatures consistently exceed 600°C (1112°F)** 2. **Conventional steels fail due to thermal softening** 3. **Application involves brass, bronze, or copper alloys** 4. **High wear resistance at temperature is required** 5. **Extended tool life justifies premium material cost** ### **When to Consider Alternatives:** 1. **Operating below 550°C (1022°F)** 2. **High impact loads at room temperature** 3. **Cost sensitivity outweighs performance benefits** 4. **Complex geometries requiring extensive machining** 5. **Frequent welding repairs anticipated** ## **Technical Support Services** ### **Available from Böhler-Uddeholm:** 1. **High-Temperature Application Analysis:** Material selection guidance 2. **Heat Treatment Optimization:** For high-temperature properties 3. **Failure Analysis:** Specialized for high-temperature failures 4. **Application Engineering:** Design for high-temperature service 5. **Processing Workshops:** Machining and heat treatment training ### **Documentation Provided:** - **High-Temperature Property Data:** Detailed performance characteristics - **Heat Treatment Guidelines:** Optimized for high-temperature applications - **Application Case Studies:** Real-world brass and bronze casting examples - **Processing Manuals:** Specialized for high-alloy tool steels - **Safety Guidelines:** For high-temperature tool handling --- ## **Critical Technical Notes** ### **Unique Advantages of HOTVAR:** 1. **Proven High-Temperature Performance:** Documented success in brass casting 2. **Tungsten-Based Alloy System:** Superior to chromium systems at high temperature 3. **Balanced Properties:** Good combination of hot hardness, wear resistance, and toughness 4. **Manufacturing Expertise:** Uddeholm proprietary knowledge and quality control ### **Limitations and Considerations:** 1. **Not for Low-Temperature Applications:** Below 500°C, other steels may be better 2. **Machining Difficulty:** Challenging even in annealed condition 3. **Weldability Concerns:** Repair welding difficult and often unsuccessful 4. **Cost Premium:** Significant investment required 5. **Heat Treatment Sensitivity:** Requires precise control for optimal properties ### **Industry Acceptance:** - **Well-established** in brass and bronze die casting industry - **Proven performance** in glass molding applications - **Recognized as premium solution** for high-temperature challenges - **Used by leading manufacturers** worldwide for demanding applications --- **Disclaimer:** UDDEHOLM HOTVAR is a specialized high-temperature hot work tool steel that should be selected only for applications where its high-temperature advantages are necessary and justified. Consult with Böhler-Uddeholm technical specialists to determine if this material is appropriate for your specific high-temperature application. Performance data based on laboratory testing and field experience; actual performance may vary with specific operating conditions and heat treatment. Always follow current technical documentation and safety guidelines. Proper application design, precise heat treatment, and appropriate maintenance are essential for achieving optimal performance with HOTVAR. -:- For detailed product information, please contact sales. -: Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6861 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. -: Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Wire -:- For detailed product information, please contact sales. -:

Packing of Bohler-Uddeholm UDDEHOLM HOTVAR® Hot Work Tool Steel Wire -:- 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 3332 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