International Mold Steel Sheet,Plate,S-Star 420 ESR Stainless Steel Sheet,Plate for Plastic Molds

International Mold Steel Sheet/Plate S-Star 420 ESR Stainless Steel Sheet/Plate for Plastic Molds Product Information -:- For detailed product information, please contact sales. -: International Mold Steel Sheet/Plate S-Star 420 ESR Stainless Steel Sheet/Plate for Plastic Molds Synonyms -:- For detailed product information, please contact sales. -:

International Mold Steel S-Star 420 ESR Stainless Steel for Plastic Molds Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: S-Star 420 ESR Stainless Steel for Plastic Molds** ## **1. Overview** **S-Star 420 ESR** is a **premium-grade, martensitic stainless mold steel** produced via the **Electro-Slag Remelting (ESR)** process to achieve exceptional purity, homogeneity, and polishability. As an advanced member of the AISI 420 stainless steel family, it is specifically engineered for high-precision plastic injection molds requiring **superior corrosion resistance, excellent mirror polishability, and flawless texture transfer**. The ESR refining process eliminates non-metallic inclusions and creates an ultra-fine, isotropic microstructure, enabling this steel to achieve perfect surface finishes (up to SPI A1 mirror class) while providing outstanding resistance to corrosive plastics, moisture, and chemical cleaning agents. It is the material of choice for optical, medical, and consumer electronic molds where surface quality and corrosion resistance are paramount. ## **2. International Standards & Specifications** This material is a proprietary premium grade that exceeds standard industry specifications for 420-type stainless mold steels. * **Primary Manufacturer Standard:** * **International Mold Steel (IMS) S-Star 420 ESR:** Proprietary specification for the premium ESR-refined stainless steel. * **Base Material International Equivalents:** * **AISI 420 (Modified) / UNS S42000:** American standard martensitic stainless steel. * **DIN 1.2083 / 1.2085:** The most common European stainless mold steel grades. S-Star is a superior, cleaner version of 1.2083. * **JIS G4303 SUS420J2:** Japanese stainless steel equivalent. * **ISO 4957 X40Cr13:** International standard classification. * **Industry Benchmark:** Positioned as a **high-purity, isotropic alternative to standard 1.2083/420**, competing with other premium stainless grades like **Stavax ESR (Uddeholm)** and **M300 ESR (Böhler)**. ## **3. Chemical Composition (Weight %, Typical)** The composition is balanced for optimal corrosion resistance, hardenability, and most critically, polishability. | Element | Typical Range (%) | Role & Benefit | | :--- | :--- | :--- | | **Carbon (C)** | 0.38 – 0.42 | Provides the necessary hardness and wear resistance after heat treatment. Tightly controlled for consistency. | | **Chromium (Cr)** | 12.80 – 13.50 | **Primary alloy.** Confers **excellent corrosion resistance** by forming a protective passive chromium oxide (Cr₂O₃) layer. Essential for resisting moisture and corrosive plastic additives. | | **Molybdenum (Mo)** | (May be present, ~0.15-0.30) | Often added in premium grades to enhance corrosion resistance (especially pitting), hardenability, and toughness. | | **Vanadium (V)** | (May be present, ~0.05-0.15) | Added for grain refinement and to improve wear resistance. | | **Manganese (Mn)** | ≤ 0.60 | Aids in deoxidation and hot workability. | | **Silicon (Si)** | ≤ 0.40 | Deoxidizer, improves fluidity. | | **Sulfur (S)** | **≤ 0.001 (Ultra-Low)** | **The critical differentiator.** Kept at an extremely low level (**"S-Free"**) to eliminate sulfide inclusions (MnS), which are the primary obstacle to achieving perfect mirror polishes. This is the key to its **exceptional polishability**. | | **Phosphorus (P)** | ≤ 0.015 | Impurity, minimized to ensure good toughness. | ## **4. Typical Physical & Mechanical Properties** * **Standard Delivery Condition:** **Pre-hardened and tempered** to approximately **30-34 HRC (290-330 HB)**, ready for machining. Can also be supplied soft-annealed (~200 HB) for hobbing or extensive machining. * **Properties in Pre-Hardened State (30-34 HRC):** * **Tensile Strength:** ~ 1000 – 1100 MPa (145,000 – 160,000 psi) * **Yield Strength (0.2% Offset):** ~ 850 – 950 MPa (123,000 – 138,000 psi) * **Elongation:** ≥ 12% * **Impact Toughness:** Adequate for mold applications. * **Properties After Final Hardening & Tempering:** * **Austenitizing:** 1020-1050°C (1868-1922°F), oil or air quench. * **Tempering:** 250-550°C (480-1020°F) depending on required hardness/toughness balance. * **Achievable Hardness:** **48 – 52 HRC** (typical for corrosion-resistant cavities). * **Dimensional Stability:** Good, with moderate distortion during hardening. * **Physical Properties:** * **Density:** 7.75 g/cm³ * **Thermal Conductivity:** ~ 25 W/m·K (at 20°C) * **Coefficient of Thermal Expansion:** ~ 10.5 x 10⁻⁶/K (20-100°C) * **Corrosion Resistance:** **Excellent.** Superior to standard P20 and H13 steels. Resists rust from cooling water, humidity, and acidic decomposition products from plastics (e.g., PVC, flame-retardant materials). * **Key Performance Feature – Polishability:** * **SPI Finish:** Capable of achieving **#A1 Mirror Polish** (the highest grade, <0.05μm Ra). * **Texture Transfer:** Perfect replication of fine etch textures (e.g., VDI 3400 textures) due to the homogeneous, inclusion-free ESR microstructure. ## **5. Product Application** S-Star 420 ESR is specified for high-end plastic molds where surface finish and corrosion are critical concerns. * **Optical and Lens Molds:** For cameras, eyeglasses, LED lenses, light guides, and reflectors requiring flawless optical surfaces. * **Medical Device Molds:** For syringes, implants, diagnostic equipment, and housings where cleanability and corrosion resistance are mandatory. * **Consumer Electronics Molds:** For high-gloss housings of mobile phones, laptops, TVs, and wearables. * **Molds for Corrosive Plastics:** * **Polyvinyl Chloride (PVC)** * **Flame-Retardant (FR) plastics** (containing halogen or phosphorus) * **Polyacetals** and other plastics that release acids during processing. * **Food Packaging and Transparent Part Molds:** Where clarity and hygiene are important. * **General High-Polish Molds:** For automotive interior trims, cosmetic packaging, and any part requiring a Class A surface finish. ## **6. Key Features & Advantages** * **Exceptional Mirror Polishability:** The **ESR process and ultra-low sulfur content** are the foundation for achieving defect-free, high-reflection mirror surfaces, eliminating pits and streaks caused by inclusions. * **Superior Corrosion Resistance:** High chromium content provides excellent protection against rust and chemical attack, extending mold life and reducing maintenance downtime. * **Excellent Texture Etching Performance:** The homogeneous structure allows for precise and uniform etching of complex textures (VDI, MT, leather grains). * **Good Machinability and EDM Performance:** In the pre-hardened state, it offers good machinability. It also performs well in electrical discharge machining. * **Isotropic Properties:** The ESR structure ensures uniform mechanical and thermal properties in all directions, crucial for predictable mold behavior and performance. * **Weldability:** Can be repaired using matching stainless filler rods with proper pre-heat and post-weld heat treatment procedures. * **Nitriding Suitability:** Responds well to gas or plasma nitriding to further increase surface hardness (>1000 HV) and wear resistance without compromising corrosion resistance. ## **7. Processing Guidelines** * **Machining:** Use standard tooling for pre-hardened steels. For best results in the hardened state, use carbide tools. * **Polishing:** Follow a sequential grit progression. The material's cleanliness allows for efficient polishing to high grades. * **Heat Treatment:** If hardening is required, use vacuum or protective atmosphere furnaces to prevent decarburization and oxidation. * **Maintenance:** Regular cleaning and application of protective oils during storage are recommended to maintain the corrosion-resistant surface. **Summary:** International Mold Steel S-Star 420 ESR is a premier stainless mold steel designed for the most demanding applications in plastic injection molding. By combining the inherent corrosion resistance of AISI 420 stainless steel with the unparalleled cleanliness and homogeneity of the Electro-Slag Remelting process, it delivers the perfect substrate for optical-quality surfaces and complex textures. For molders producing high-value, cosmetic, or corrosive plastic components, S-Star 420 ESR provides the essential combination of stunning surface finish, long-term durability, and reliable performance. -:- For detailed product information, please contact sales. -: International Mold Steel S-Star 420 ESR Stainless Steel for Plastic Molds Specification Dimensions Size： Diameter 20-1000 mm Length <7030 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. -: International Mold Steel S-Star 420 ESR Stainless Steel for Plastic Molds Properties -:- For detailed product information, please contact sales. -:

Applications of International Mold Steel Sheet,Plate S-Star 420 ESR Stainless Steel Sheet,Plate for Plastic Molds -:- For detailed product information, please contact sales. -: Chemical Identifiers International Mold Steel Sheet,Plate S-Star 420 ESR Stainless Steel Sheet,Plate for Plastic Molds -:- For detailed product information, please contact sales. -:

Packing of International Mold Steel Sheet/Plate S-Star 420 ESR Stainless Steel Sheet/Plate for Plastic Molds -:- 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 Sheet/Plate 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 3501 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