Schmolz + Bickenbach,Cryodur® 2357(S-7) Cold Work Die Steel Wire

Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Wire Product Information -:- For detailed product information, please contact sales. -: Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Product Information -:- For detailed product information, please contact sales. -: # **SCHMOLZ + BICKENBACH Cryodur® 2357 (S-7) | Premium Shock-Resistant Cold Work Tool Steel** ## **Overview** SCHMOLZ + BICKENBACH **Cryodur® 2357** is a premium-grade, silicon-chromium alloyed cold work tool steel corresponding to the AISI S7 (DIN 1.2357) classification. Renowned for its **exceptional combination of high toughness, good wear resistance, and deep hardenability**, this air-hardening steel is specifically engineered for applications demanding resistance to shock loading, impact, and fatigue. The "Cryodur®" designation signifies production to the highest quality standards, ensuring superior microstructural homogeneity and consistent performance. S-7 type steels are characterized by their ability to maintain hardness at elevated temperatures (secondary hardening) while providing the toughness necessary for severe service conditions. ## **Key Features:** * **Exceptional Toughness:** Offers the highest impact resistance among commonly used cold work tool steels, making it ideal for applications subject to shock loading, bending, or high stress concentrations. * **Good Wear Resistance:** Provides adequate abrasion resistance for many cold work applications, particularly when hardened to its maximum potential (58-60 HRC). * **Deep Air-Hardening:** Exhibits excellent hardenability, allowing through-hardening of large sections with minimal distortion due to its air-quenching characteristics. * **Good High-Temperature Stability:** Shows secondary hardening during tempering, enabling maintenance of hardness at slightly elevated service temperatures (up to ~300°C). * **Minimal Distortion:** Air hardening results in significantly less distortion and lower risk of cracking compared to oil-hardening steels of similar section size. * **Good Machinability:** In the annealed condition, offers reasonable machinability for a tool steel of its alloy content. * **Excellent Grindability:** Responds well to grinding operations, allowing for precise finishing. * **Good Dimensional Stability:** Predictable behavior during heat treatment facilitates production of precision tools. --- ## **Material Specifications: Cryodur® 2357 (S-7)** ### **1. Chemical Composition (wt%)** | Element | Content Range (wt%) | Function & Metallurgical Benefit | | :--- | :--- | :--- | | **Carbon (C)** | 0.45 - 0.55 | Provides matrix hardness and wear resistance. Balanced for optimal toughness. | | **Silicon (Si)** | 1.80 - 2.20 | **Key element.** Enhances toughness, promotes secondary hardening during tempering, and increases resistance to softening at elevated temperatures. | | **Manganese (Mn)** | 0.60 - 1.00 | Improves hardenability and strength. | | **Chromium (Cr)** | 3.00 - 3.50 | Provides hardenability, wear resistance, and contributes to secondary hardening. | | **Molybdenum (Mo)** | 1.30 - 1.70 | Enhances hardenability, strength, and toughness. Improves high-temperature properties. | | **Vanadium (V)** | ≤ 0.25 (often 0.15-0.25) | Optional addition for grain refinement and enhanced wear resistance. Improves toughness at lower levels. | | **Sulfur (S)** | ≤ 0.005 | Very low for optimal toughness and transverse properties. | | **Phosphorus (P)** | ≤ 0.015 | Minimized to prevent embrittlement. | **Metallurgical Characteristics:** The Si-Cr-Mo combination is key. Silicon is unusually high for a tool steel, which: 1. Strongly promotes **secondary hardening** during tempering around 500-550°C. 2. Increases the **tempering resistance**, allowing tools to maintain hardness if they heat up in service. 3. Enhances the **toughness** of the tempered martensite matrix. ### **2. Physical & Mechanical Properties** #### **Properties in Annealed Condition:** * **Hardness:** ~200 HB (max) * **Microstructure:** Spheroidized carbides in ferritic matrix. * **Machinability:** Fair to Good (for its alloy class). #### **Properties in Hardened & Tempered Condition:** | Tempering Temperature | Resulting Hardness (HRC) | 0.2% Yield Strength (MPa) | Tensile Strength (MPa) | **Impact Toughness (Charpy V, J) – Key Property** | | :--- | :--- | :--- | :--- | :--- | | **180-200°C** | 57 - 59 | ~1850 - 2000 | ~2050 - 2200 | **25 - 35** | | **300-350°C** | 56 - 58 | ~1750 - 1900 | ~1950 - 2100 | **30 - 40** | | **425-475°C** | 55 - 57 | ~1650 - 1800 | ~1850 - 2000 | **35 - 50** | | **500-540°C** | 56 - 58 **(Secondary Hardening Peak)** | ~1700 - 1850 | ~1900 - 2050 | **30 - 45** | | **580-620°C** | 48 - 52 | ~1400 - 1550 | ~1600 - 1750 | **45 - 65** | **Typical Service Condition:** For maximum toughness with good wear resistance, tempering at **425-475°C to 55-57 HRC** is common. For maximum wear resistance with good toughness, tempering at the secondary hardening peak (**500-540°C to 56-58 HRC**) is used. #### **Physical Properties:** * **Density:** ~7.75 g/cm³ * **Thermal Conductivity:** ~32 W/m·K (at 20°C) – Relatively high for a tool steel. * **Coefficient of Thermal Expansion:** 11.5 x 10⁻⁶ /K (20-100°C) * **Modulus of Elasticity:** 205 GPa * **Specific Heat Capacity:** ~460 J/kg·K ### **3. Special Performance Characteristics** * **Impact Toughness:** The standout feature. At 55-57 HRC, its impact resistance is typically **2-3 times higher** than that of D2 (1.2379) at similar hardness and significantly better than many other cold work steels. * **Fatigue Strength:** Excellent resistance to failure under cyclic loading due to its high toughness. * **Strength-Toughness Balance:** Occupies a unique position in the tool steel spectrum, offering the best practical combination of hardness and toughness for shock applications. ### **4. Machining & Finishing** * **Machining (Annealed):** Fair to Good. Use positive geometry carbide tools with moderate speeds/feeds. * **Grinding:** Good. Standard aluminum oxide wheels perform well. Avoid excessive heat input. * **EDM:** Suitable. Standard wire and sinker EDM can be used. * **Polishing:** Good. Can achieve fine finishes, though not equal to high-chromium steels like D2. * **Welding:** **Possible with caution.** Requires preheating (300-400°C), use of low-hydrogen matching electrodes, and mandatory post-weld tempering. Not generally recommended for critical tool areas. --- ## **International Standards & Cross-References** | Standard | Designation | Note | | :--- | :--- | :--- | | **SCHMOLZ + BICKENBACH** | **Cryodur® 2357** | Proprietary brand name for premium quality. | | **DIN / EN / W-Nr.** | **1.2357** | | | **AISI / ASTM** | **S7** | | | **ISO 4957** | **55SiCrMo3-2** | | | **Uddeholm** | **SLEIPNER®** | Note: SLEIPNER is a modified S7-type with higher V for better wear resistance. | | **Böhler / voestalpine** | **S500** / **S600** (S600 is similar) | | | **Japanese (JIS)** | **SKS3? / SKD?** | Not a direct common JIS equivalent; often specified as imported S7. | | **Chinese (GB)** | **5Cr3SiMnMoV** (similar concept) | | --- ## **Heat Treatment Guidelines** 1. **Soft Annealing:** Heat to 780-800°C, hold sufficiently, slow cool in furnace to 600°C (approx. 15°C/hour), then air cool. Target: ≤ 200 HB. 2. **Stress Relieving (after rough machining):** 600-650°C for 2 hours. 3. **Preheating:** Very important. Preheat at 500-550°C and 800-850°C. 4. **Austenitizing (Hardening):** * **Temperature:** **920-950°C.** Use controlled atmosphere or vacuum. * **Soak Time:** 20-30 minutes per 25mm of ruling section. 5. **Quenching:** In **still or forced air.** This is an **air-hardening steel**. Oil quenching is not necessary and increases distortion/cracking risk. For very large sections or complex shapes, high-pressure gas quenching in a vacuum furnace is ideal. 6. **Tempering:** * **Must be performed immediately** after quenching. * **Temperature:** Depending on required properties: **180-250°C** for max wear resistance; **425-540°C** for optimal toughness/hardness balance (utilizing secondary hardening). * **Double tempering is strongly recommended.** Hold for at least 2 hours per temper, air cool between tempers. * **Note:** The secondary hardness peak occurs around **500-540°C**. Tempering above 540°C will cause softening. --- ## **Product Applications** Cryodur® 2357 (S-7) is the **material of choice for cold work tooling subjected to high impact, shock loading, or bending stresses.** **Primary Application Areas:** **A. Shearing, Punching, and Blanking:** * **Punches and Dies for thick materials** or high-strength steels where edge chipping is a problem with harder, more brittle steels. * **Heavy-Duty Shear Blades.** * **Slitter Knives** for tough materials. * **Notching Tools.** **B. Forming and Stamping:** * **Cold Forming Punches and Dies** subject to high radial or bending stresses. * **Gooseneck Punches** for deep drawing. * **Forming Rolls** and **Bending Dies.** * **Swaging Tools.** **C. Shock Tools & Chisels:** * **Chisels** for metal or stone. * **Demolition Tools.** * **Driver Tools** (e.g., for pins, liners). **D. Plastic Molds (Special Cases):** * **Mold components subject to high clamping pressures or impact** (e.g., slides, lifters, ejector pins in stressed areas). * **Not typically used for cavities** due to lower polishability/wear resistance than P20-type steels. **E. Other Tooling:** * **Gripper Jaws** and **Collets.** * **Knives** for cutting abrasive but non-metallic materials where toughness is key. * **Parts for machinery** requiring high strength and fatigue resistance. **Typical Components:** * Punch holders * Bolster plates for heavy punching * Driver blocks * Gripper inserts * Forming inserts for high-strength steel **When to Choose S-7 / Cryodur® 2357:** Select this grade when **tool breakage, chipping, or cracking under impact** is the primary failure mode, and a slight compromise in absolute wear resistance is acceptable to gain tremendous toughness. It is often the solution when D2, A2, or O1 tools are failing catastrophically. --- **Disclaimer:** The information provided is based on typical data for SCHMOLZ + BICKENBACH Cryodur® 2357. Properties can vary within specification ranges and are highly dependent on precise heat treatment, especially tempering temperature. This document is for informational purposes only and does not constitute a guarantee. For critical applications, always consult the official manufacturer's technical documentation. Proper utilization of its secondary hardening characteristic is key to optimizing performance for specific applications. -:- For detailed product information, please contact sales. -: Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Specification Dimensions Size： Diameter 20-1000 mm Length <7137 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 Cryodur® 2357(S-7) Cold Work Die Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die Steel Wire -:- For detailed product information, please contact sales. -:

Packing of Schmolz + Bickenbach Cryodur® 2357(S-7) Cold Work Die 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 3608 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