Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420

Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 Product Information -:- For detailed product information, please contact sales. -: Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 Synonyms -:- For detailed product information, please contact sales. -:

Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 Product Information -:- For detailed product information, please contact sales. -: # **Böhler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 Stainless Mold Steel** ## **Product Overview** **UDDEHOLM STAVAX® ESR** is a premium **martensitic stainless chromium mold steel** manufactured using **Electro-Slag Remelting (ESR)** technology. As a modified and enhanced version of standard AISI 420 stainless steel, STAVAX® ESR delivers superior **internal cleanliness, uniform microstructure, and exceptional polishability**, making it the industry benchmark for high-quality plastic injection molds requiring mirror finishes, corrosion resistance, and reliable performance. Its optimized chemistry and advanced refining process ensure consistent properties critical for complex mold manufacturing and long production runs. --- ## **1. Key Characteristics & Advantages** * **Superb Polishability:** Capable of achieving the highest-grade mirror finishes (SPI A-1, #1 Diamond finish) due to its extremely uniform and fine microstructure free of large inclusions. * **Excellent Corrosion Resistance:** Provides very good resistance to water, humid atmospheres, and corrosive plastic decomposition products (e.g., from PVC, flame-retardant materials). * **High Wear Resistance (for a stainless steel):** Offers better wear resistance than standard 420 grades, suitable for many engineering plastics. * **Excellent Photochemical Etching (Texturing) Performance:** The clean, isotropic structure allows for precise, consistent, and high-quality surface texturing. * **Good Dimensional Stability:** Predictable and minimal distortion during heat treatment due to good hardenability and controlled processes. * **ESR Quality:** Electro-Slag Remelting ensures very low sulfur content and non-metallic inclusions, resulting in improved toughness, better machined surfaces, and enhanced polishability. * **Good Machinability:** In annealed condition, it offers favorable machining characteristics compared to many tool steels of similar hardness. --- ## **2. Typical Chemical Composition (Weight %)** | Element | Carbon (C) | Chromium (Cr) | Molybdenum (Mo) | Vanadium (V) | Silicon (Si) | Manganese (Mn) | | :--- | :---: | :---: | :---: | :---: | :---: | :---: | | **Content** | **0.38** | **13.60** | **0.30** | **0.30** | **0.90** | **0.50** | **Alloying Rationale (vs. Standard 420):** * **Carbon (0.38%):** Optimized to balance hardness, polishability, and corrosion resistance. Higher than standard 420 (~0.15-0.40%) for better wear resistance. * **Chromium (13.6%):** Provides the primary corrosion resistance by forming a passive chromium oxide layer. Slightly higher than minimum 420 requirements for enhanced performance. * **Molybdenum (0.3%) & Vanadium (0.3%):** Added to refine grain structure, improve hardenability, and increase toughness and wear resistance. These are key modifications that distinguish it from basic 420. * **Silicon (0.9%):** Enhances strength and hardenability. * **ESR Process:** Critically reduces sulfur and oxide inclusions, which are the main obstacles to perfect polishing and uniform etching. --- ## **3. Physical & Mechanical Properties** ### **Physical Properties:** * **Density:** ~7.75 g/cm³ * **Thermal Conductivity:** ~25 W/(m·K) at 20°C * **Modulus of Elasticity:** ~200 GPa * **Coefficient of Thermal Expansion:** ~10.5 x 10⁻⁶/K (20-100°C) * **Magnetic Properties:** Magnetic in both annealed and hardened conditions. ### **Heat Treatment & Mechanical Data:** * **Annealed Hardness:** ~215 HBW * **Austenitizing Temperature:** 1020 - 1050°C (1870 - 1920°F) * **Quenching Medium:** Oil or air (for smaller sections). Vacuum or controlled atmosphere furnace is mandatory to prevent decarburization. * **Tempering Temperature Range:** 180 - 350°C (355 - 660°F). **Double tempering is recommended.** * **Achievable Hardness:** **50 - 54 HRC** * Typical working hardness for plastic molds is **50-52 HRC** (tempered at ~250-300°C), offering an optimal balance of polishability, strength, and corrosion resistance. * **Impact Toughness:** Good for a stainless mold steel. * **Corrosion Resistance:** Between that of AISI 420 and 440A. Adequate for most plastic molding environments except the most severely corrosive. --- ## **4. Primary Applications** STAVAX® ESR is the premier choice for high-surface-quality plastic injection molds, especially where aesthetics are critical. * **Plastic Injection Molds:** * **Optical Components:** Lenses, light guides, reflectors, and covers requiring flawless optical clarity. * **Consumer Electronics & Automotive Interiors:** High-gloss bezels, panels, and trims (e.g., TV frames, appliance parts). * **Medical Devices:** Transparent components, housings requiring easy cleaning and corrosion resistance. * **Packaging:** Cosmetic containers, lids. * **Molds for Corrosive Plastics:** PVC, polyacetals, flame-retardant (FR) materials, and other acid-releasing polymers. * **Die Casting:** Ejector pins and cores for aluminum/zinc, benefiting from its corrosion and soldering resistance. * **General Precision Engineering:** Components requiring good corrosion resistance and a high-quality surface finish. --- ## **5. Relevant International Standards & Comparable Grades** STAVAX® ESR is a proprietary modified grade. The closest generic equivalents are based on AISI 420, but the modifications and ESR quality make it a superior performer. | Standard | Grade / Designation | Country/Region | Similarity / Key Difference | | :--- | :--- | :--- | :--- | | **Proprietary (Uddeholm)** | **STAVAX® ESR** | International | The reference premium modified 420 ESR steel. | | **AISI / ASTM A681** | **420 Modified** | USA | STAVAX fits this broad category but has specified Mo/V additions and guaranteed ESR quality. | | **DIN / Werkstoff** | **1.2083 / X42Cr13** | Germany/EU | The most common European equivalent. STAVAX typically has slightly optimized chemistry and the guaranteed benefits of ESR refining. | | **JIS G4203** | **SUS420J2** | Japan | The Japanese stainless tool steel. STAVAX offers more consistent quality and polishability. | | **Other Premium Grades** | **M300 Series (e.g., M310)** | Various | Other proprietary pre-hardened stainless mold steels. STAVAX is supplied annealed for full machinability and custom heat treatment. | | **ESR Quality Designation** | **ESR / VAR** | N/A | The process (Electro-Slag Remelted) is a key differentiator from standard air-melted 1.2083/420. | **Important:** "**STAVAX® ESR**" should be specified to ensure receipt of Uddeholm's premium-grade material with guaranteed polishability and consistency. --- ## **6. Processing & Fabrication Guidelines** * **Machining:** All heavy machining should be done in the **soft-annealed condition**. It machines well with sharp carbide tools. Good chip control and coolant are recommended. * **Heat Treatment:** **Must be hardened in a vacuum or protective atmosphere furnace** to prevent surface decarburization and oxidation, which would ruin polishability. Preheating is recommended. Double tempering improves toughness and dimensional stability. * **Stress Relieving:** After rough machining and before finishing, a stress relief at 600-650°C is advisable, especially for complex molds. * **Grinding & Polishing:** The ESR structure is ideal for finishing. Use systematic abrasive and diamond polishing steps. Its cleanliness prevents "pitting" or "orange peel" effects during high-grade polishing. * **Photochemical Etching (Texturing):** Excellent performance due to uniform material removal. Produces sharp, consistent textures. * **Welding:** Can be welded with proper precautions. Use matching analysis filler wire (e.g., UDDEHOLM CORRAX welding wire or similar stainless grade). Pre-heat to 300°C and post-heat treat (re-harden and temper) for critical applications. * **Surface Treatment:** PVD coatings (CrN, TiN) can be applied to further enhance wear and release properties. --- ## **7. Conclusion** **UDDEHOLM STAVAX® ESR** represents the gold standard for plastic injection mold steels where **superior surface finish, corrosion resistance, and reliable manufacturing are paramount.** Its modified chemistry and ESR refining process directly address the limitations of standard 420 stainless steels, providing mold makers with a predictable, high-performance material capable of producing millions of high-quality parts. For applications demanding flawless aesthetics—from consumer electronics to optical components—or for molding corrosive plastics, STAVAX® ESR offers an unparalleled combination of polishability, durability, and consistency. It is the definitive choice when the quality of the molded part's surface is a direct reflection of the tool steel from which the mold is made. -:- For detailed product information, please contact sales. -: Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 Specification Dimensions Size： Diameter 20-1000 mm Length <6884 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 STAVAX® ESR Modified 420 Properties -:- For detailed product information, please contact sales. -:

Applications of Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 -:- For detailed product information, please contact sales. -: Chemical Identifiers Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 -:- For detailed product information, please contact sales. -:

Packing of Bohler-Uddeholm UDDEHOLM STAVAX® ESR Modified 420 -:- 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 3355 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