Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel

Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel Product Information -:- For detailed product information, please contact sales. -: Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel Synonyms -:- For detailed product information, please contact sales. -:

Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel Product Information -:- For detailed product information, please contact sales. -: # **SCHMOLZ + BICKENBACH Thermodur® 2365 EFS (Extra Fine Structure) | Premium High-Temperature Hot Work Die Steel** ## **Overview** SCHMOLZ + BICKENBACH **Thermodur® 2365 EFS (Extra Fine Structure)** is a premium-grade, high-chromium hot work die steel engineered for applications demanding **exceptional high-temperature strength, thermal stability, and oxidation resistance**. Based on the AISI H10 / DIN 1.2365 alloy system, this ESR-refined (Electroslag Remelted) material represents a significant advancement over conventional hot work steels, offering superior performance in the most severe thermal environments where temperatures routinely exceed 600°C (1112°F). The **"EFS"** designation signifies an ultra-homogeneous, inclusion-controlled microstructure that delivers **enhanced thermal fatigue resistance, improved toughness, and consistent high-temperature properties** for demanding die casting, forging, and hot forming applications. ## **Key Features:** * **Exceptional High-Temperature Strength:** Maintains superior hardness and strength at temperatures up to 650°C (1202°F), outperforming conventional H13/H11 grades in sustained high-temperature applications. * **Excellent Oxidation Resistance:** High chromium content (approx. 7%) forms a stable, protective oxide layer, significantly reducing scaling and surface degradation in oxidizing atmospheres. * **Extra Fine Structure (EFS):** ESR refining produces an isotropic, ultra-clean microstructure with minimal segregation, enhancing thermal fatigue life and mechanical property consistency. * **Superior Thermal Conductivity:** Approximately 20-25% higher thermal conductivity than H13 grades, promoting efficient heat extraction and reducing thermal gradients. * **Good Thermal Fatigue Resistance:** The fine, homogeneous structure combined with high thermal conductivity provides excellent resistance to heat checking under thermal cycling conditions. * **High Toughness at Elevated Temperatures:** Maintains good impact resistance even at operating temperatures, reducing susceptibility to crack initiation. * **Good Dimensional Stability:** Predictable heat treatment response with minimal distortion due to its air-hardening characteristics and uniform microstructure. * **Excellent Polishability:** The clean EFS structure allows for superior surface finishes, reducing sticking and improving part release characteristics. --- ## **Material Specifications: Thermodur® 2365 EFS** ### **1. Chemical Composition (wt%)** | Element | Content Range (wt%) | Function & High-Temperature Benefit | | :--- | :--- | :--- | | **Carbon (C)** | 0.32 - 0.40 | Provides matrix strength and hardness. Balanced for optimal toughness at high temperatures. | | **Silicon (Si)** | 0.80 - 1.20 | Enhances oxidation resistance and high-temperature strength. | | **Manganese (Mn)** | 0.20 - 0.50 | Aids in deoxidation and contributes to hardenability. | | **Chromium (Cr)** | **6.80 - 7.50** | **Key Element.** Provides exceptional oxidation resistance, deep hardenability, and high-temperature strength. Forms stable Cr-rich carbides. | | **Molybdenum (Mo)** | 2.80 - 3.20 | **Critical for High-Temperature Performance.** Enhances hot strength, tempering resistance, and creep resistance. Provides secondary hardening. | | **Vanadium (V)** | 0.40 - 0.60 | Forms fine, stable carbides that improve wear resistance and contribute to grain refinement. | | **Tungsten (W)** | 1.20 - 1.50 | Enhances hot hardness and tempering resistance through solid solution strengthening. | | **Cobalt (Co)** | 0.30 - 0.60 (Optional) | Can be added to further enhance hot hardness and tempering resistance in specialized variants. | | **Sulfur (S)** | **≤ 0.003** (EFS) | **Ultra-Low.** Essential for maximizing transverse toughness and polishability. | | **Phosphorus (P)** | **≤ 0.015** (EFS) | **Ultra-Low.** Minimized to prevent high-temperature embrittlement. | **Metallurgical Advantages of EFS Structure:** * **Inclusion Control:** ESR process reduces oxide and sulfide inclusions by >90%, eliminating potential crack initiation sites. * **Chemical Homogeneity:** Eliminates micro-segregation, ensuring uniform distribution of alloying elements. * **Fine Grain Structure:** Produces ASTM 10-12 grain size, enhancing both strength and toughness. * **Isotropic Properties:** Near-identical mechanical properties in all directions due to uniform microstructure. ### **2. Physical & Mechanical Properties** #### **Properties in Annealed Condition:** * **Hardness:** 190 - 220 HB * **Microstructure:** Fine, uniformly spheroidized carbides in ferritic matrix * **Machinability:** Fair to Good (similar to other high-alloy hot work steels) #### **Properties in Hardened & Tempered Condition:** | Tempering Temperature | Hardness (HRC) | 0.2% Yield Strength (MPa) | Tensile Strength (MPa) | Impact Toughness (KV, J) | | :--- | :--- | :--- | :--- | :--- | | **560-580°C** | 48 - 50 | 1550 - 1700 | 1750 - 1900 | 25 - 35 | | **600-620°C** | 46 - 48 | 1400 - 1550 | 1600 - 1750 | 30 - 40 | | **640-660°C** | 44 - 46 | 1300 - 1450 | 1500 - 1650 | 35 - 50 | | **680-700°C** | 42 - 44 | 1200 - 1350 | 1400 - 1550 | 40 - 60 | #### **High-Temperature Performance (Tempered to 48 HRC):** | Temperature | Hot Hardness (HV) | 0.2% Hot Yield Strength (MPa) | Retained Room-Temp Hardness | Thermal Conductivity | | :--- | :--- | :--- | :--- | :--- | | **500°C** | 450 - 480 | 1000 - 1150 | ~85% | 30 - 33 W/m·K | | **600°C** | 380 - 420 | 700 - 850 | ~70% | 28 - 31 W/m·K | | **650°C** | 320 - 360 | 500 - 650 | ~60% | 27 - 30 W/m·K | | **700°C** | 260 - 300 | 350 - 500 | ~50% | 26 - 29 W/m·K | #### **Comparative High-Temperature Performance:** | Property @ 600°C | Thermodur® 2365 EFS | Standard H13 (1.2344) | Improvement | | :--- | :--- | :--- | :--- | | **Hot Hardness** | 380-420 HV | 300-340 HV | **+25-30%** | | **Hot Yield Strength** | 700-850 MPa | 500-600 MPa | **+35-40%** | | **Oxidation Resistance** | Excellent | Good | **Significantly Better** | | **Thermal Conductivity** | 28-31 W/m·K | 22-24 W/m·K | **+25-30%** | #### **Physical Properties:** * **Density:** 7.85 g/cm³ * **Coefficient of Thermal Expansion:** 11.2 × 10⁻⁶/K (20-400°C) * **Modulus of Elasticity:** 215 GPa * **Specific Heat Capacity:** 450 J/kg·K * **Maximum Service Temperature:** **700°C (1292°F)** for intermittent service ### **3. Special Performance Characteristics** * **Thermal Fatigue Life:** The combination of high thermal conductivity, fine EFS structure, and good high-temperature toughness typically provides **30-50% longer thermal fatigue life** compared to conventional H13 in high-temperature applications. * **Oxidation Resistance:** Weight loss in air at 600°C is approximately **50% lower** than standard H13, significantly reducing scaling and surface degradation. * **Creep Resistance:** Superior resistance to deformation under sustained load at high temperatures due to Mo and W alloying. * **Isotropic Toughness:** Transverse impact values are within 10% of longitudinal values, critical for dies with complex stress states. ### **4. Machining & Finishing** * **Machining (Annealed):** Use sharp carbide tools with moderate speeds and feeds. More demanding than H13 due to higher alloy content. * **EDM:** Excellent performance with stable machining characteristics. The clean structure produces minimal white layer. * **Grinding:** Good grindability with appropriate wheels (aluminum oxide or CBN) and adequate coolant. * **Polishing:** Capable of achieving very fine surface finishes (Ra < 0.3 µm) due to the homogeneous, inclusion-free structure. * **Welding:** Possible with strict procedures. Requires high preheat (400-450°C), matching filler, and post-weld tempering. Not generally recommended for critical areas. --- ## **International Standards & Cross-References** | Standard | Designation | Note | | :--- | :--- | :--- | | **SCHMOLZ + BICKENBACH** | **Thermodur® 2365 EFS** | Proprietary premium grade. | | **DIN / EN / W-Nr.** | **1.2365** (ESR Quality) | Base standard designation. | | **AISI / ASTM** | **H10** (Modified) | Similar classification, though exact compositions may vary. | | **ISO 4957** | **X32CrMoCoV3-3-3** | Similar high-temperature grade. | | **Uddeholm** | **HOTVAR®** | Similar high-temperature hot work steel. | | **Böhler / voestalpine** | **W400** | Similar grade category. | | **ThyssenKrupp** | **GS-365 ESU** | Equivalent ESR quality. | | **Japanese (JIS)** | **SKD7** | Similar high-temperature grade. | | **Chinese (GB)** | **3Cr3Mo3W2V** | Similar composition concept. | --- ## **Heat Treatment Guidelines** 1. **Soft Annealing:** 850-880°C, slow furnace cool (15-20°C/hour) to 600°C, then air cool. Target: 190-220 HB. 2. **Stress Relieving:** 650-700°C for 2-4 hours after rough machining. 3. **Preheating:** **Critical.** Three-stage preheat recommended: 500°C, 800°C, and 950°C. 4. **Austenitizing:** * **Temperature:** **1040-1080°C** (higher than H13 to ensure complete dissolution of carbides). * **Atmosphere:** Vacuum or controlled atmosphere mandatory. * **Soak Time:** 20-40 minutes per 25mm section. 5. **Quenching:** In **forced air** or **high-pressure gas** (5-10 bar). Oil quenching possible but increases distortion risk. 6. **Tempering:** * **Begin immediately** after quenching (at 40-80°C). * **Temperature:** **600-680°C** for typical hot work applications. * **Double or Triple Tempering essential.** Hold 2-3 hours per temper, air cool between tempers. * **Note:** Exhibits strong secondary hardening peak around 550-600°C. **Special Consideration:** Due to its high alloy content, 2365 EFS has a higher Ac1 temperature (~850°C) than H13, allowing for higher tempering temperatures without significant softening. --- ## **Product Applications** Thermodur® 2365 EFS is specifically engineered for **extreme high-temperature hot work applications** where conventional H11/H13 steels lack sufficient temperature capability or oxidation resistance. ### **Primary Application Areas:** **A. High-Temperature Die Casting:** * **Copper and Brass Die Casting:** Where melt temperatures exceed 900°C (1652°F). * **Aluminum Die Casting with High Iron Content:** Where increased soldering and erosion occur. * **Shot Sleeves and Goosenecks** for high-temperature alloys. * **Hot Chamber Magnesium Die Casting** components exposed to prolonged high temperatures. **B. Hot Forging and Extrusion:** * **Dies for Superalloy Forging** (Inconel, Waspaloy, etc.). * **Titanium and Titanium Alloy Forging Dies.** * **Hot Extrusion Dies and Mandrels** for stainless steels and high-temperature alloys. * **Die Inserts for Isothermal Forging.** **C. Special High-Temperature Applications:** * **Glass Molding Tools** for optical and technical glass. * **Hot Runner Systems** for high-temperature engineering plastics (PEEK, PEI, PPS). * **Tools for Hot Cutting and Shearing** of high-temperature materials. * **Die Components in Continuous Casting** lines. **D. General Hot Work Where H13 Fails:** * Applications where H13 exhibits excessive softening, scaling, or thermal fatigue above 550°C continuous operation. * Tools requiring extended exposure to high temperatures with minimal maintenance. ### **Specific Component Recommendations:** * **Core Pins and Inserts** in high-temperature die casting * **Die Cavities** for copper alloy casting * **Forging Die Inserts** for aerospace components * **Extrusion Dies** for high-alloy steels * **Hot Work Punches** subject to extreme temperatures ### **Economic Justification:** * **Extended Tool Life:** 2-3× longer life than H13 in high-temperature applications * **Reduced Maintenance:** Lower oxidation reduces cleaning and refurbishment frequency * **Improved Productivity:** Ability to run at higher temperatures or longer cycles * **Superior Part Quality:** Better surface integrity and dimensional control at high temperatures --- ## **Selection Guidelines: When to Choose 2365 EFS** **Choose Thermodur® 2365 EFS when:** 1. Operating temperatures consistently exceed **550°C (1022°F)** 2. **Oxidation and scaling** are significant problems with current tooling 3. Applications involve **copper, brass, or high-temperature alloys** 4. Tools require **sustained high-temperature strength** beyond H13 capabilities 5. **Thermal fatigue** at high temperatures is the primary failure mode 6. **Creep resistance** under load at high temperatures is critical **Consider H13 (1.2344) for:** Aluminum die casting, general hot forging below 550°C, and applications where the higher cost of 2365 EFS cannot be justified by temperature requirements. --- **Disclaimer:** The information provided is based on typical data for SCHMOLZ + BICKENBACH Thermodur® 2365 EFS. This is a premium, specialized grade requiring precise heat treatment. Properties are influenced by exact processing parameters and section size. This document is for informational purposes only and does not constitute a specification or warranty. For critical applications, always consult the official manufacturer's technical documentation. The "EFS" quality is essential for achieving the stated high-temperature performance advantages. Successful application requires careful consideration of temperature profiles and failure mechanisms in the specific process. -:- For detailed product information, please contact sales. -: Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel Specification Dimensions Size： Diameter 20-1000 mm Length <7133 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. -: Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel -:- For detailed product information, please contact sales. -: Chemical Identifiers Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel -:- For detailed product information, please contact sales. -:

Packing of Schmolz + Bickenbach Thermodur® 2365 EFS Extra Fine Structure - Hot Work Die Steel -:- 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 3604 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