ATI Allegheny Ludlum 420ESR Tool Steel Sheet,Plate, UNS S42000

ATI Allegheny Ludlum 420ESR Tool Steel Sheet/Plate, UNS S42000 Product Information -:- For detailed product information, please contact sales. -: ATI Allegheny Ludlum 420ESR Tool Steel Sheet/Plate, UNS S42000 Synonyms -:- For detailed product information, please contact sales. -:

ATI Allegheny Ludlum 420ESR Tool Steel, UNS S42000 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: ATI Allegheny Ludlum 420 ESR Tool Steel (UNS S42000)** ## **1. Overview** **ATI Allegheny Ludlum 420 ESR** is a premium **martensitic stainless tool steel** manufactured via the **Electro-Slag Remelting (ESR) process**, delivering exceptional purity, homogeneity, and performance for the most demanding plastic mold and corrosion-resistant tooling applications. Representing the highest quality tier of AISI 420 stainless steel (UNS S42000), this material is engineered to provide **superior corrosion resistance, excellent polishability, and outstanding dimensional stability**. The ESR refining process eliminates non-metallic inclusions and creates an ultra-fine, isotropic microstructure, enabling flawless mirror-like surface finishes (SPI A1) and perfect replication of fine textures. ATI 420 ESR is the material of choice for optical, medical, and high-gloss consumer product molds where surface quality, cleanability, and resistance to corrosive processing environments are critical. ## **2. International Standards & Specifications** This material represents a premium execution of a widely recognized international stainless tool steel standard. * **Primary Standard Designations:** * **UNS S42000:** Unified Numbering System designation for martensitic stainless steel. * **AISI 420:** American Iron and Steel Institute classification. * **ASTM A681:** Standard Specification for Tool Steels Alloy. * **Key International Equivalents (Premium ESR Quality):** * **DIN 1.2083 ESR / 1.2316 ESR:** The premium European equivalents for plastic mold steels, with 1.2316 having higher Mo content. * **JIS G4404 SUS420J2 (ESR):** Japanese high-grade stainless tool steel. * **ISO 4957 X40Cr13 (ESR):** International standard classification for remelted quality. * **Common Trade Names:** Marketed as **420 ESR, Stainless Mold Steel ESR**, or under proprietary names like **Stavax ESR**. ## **3. Chemical Composition (Weight %, per ASTM A681 - Typical for Premium 420 ESR)** The composition is tightly controlled for optimal corrosion resistance, hardenability, and most critically, polishability. | Element | Composition Range (%) | Role & Benefit | |---------|----------------------|----------------| | **Carbon (C)** | 0.38 – 0.45 | Provides hardness and wear resistance after heat treatment. Precisely controlled for consistent hardening response. | | **Chromium (Cr)** | 12.00 – 14.00 | **Primary corrosion-resisting element.** Forms a protective, self-healing passive chromium oxide (Cr₂O₃) layer, providing **excellent resistance to rust and chemical attack** from moisture, cooling water, and acidic plastic by-products. | | **Molybdenum (Mo)** | May be present (0.5-1.0%) in modified grades | Enhances pitting corrosion resistance, hardenability, and toughness. Often added in "420 Modified" or "1.2316-type" grades. | | **Manganese (Mn)** | ≤ 1.00 | Aids in deoxidation and hot workability. | | **Silicon (Si)** | ≤ 1.00 | Deoxidizer, improves fluidity and oxidation resistance. | | **Vanadium (V)** | May be present in small amounts | Added for grain refinement. | | **Sulfur (S)** | **≤ 0.005 (Ultra-Low - ESR Key Feature)** | **Critical for polishability.** The ESR process and tight control reduce sulfur to extremely low levels, virtually eliminating sulfide inclusions (MnS). This prevents pits and streaks during polishing, enabling **SPI A1 mirror finishes**. | ## **4. Typical Physical & Mechanical Properties** * **Common Delivery Conditions:** Can be supplied **annealed (~200 HB)** for hobbing/machining, or **prehardened (~30-34 HRC)** for direct machining of molds. * **Properties After Final Hardening & Tempering:** * **Austenitizing:** 980-1050°C (1800-1920°F) in vacuum or protective atmosphere. * **Quenching:** Air or oil. * **Tempering:** 200-550°C (390-1020°F) depending on required hardness/toughness balance. * **Achievable Hardness:** **48 – 55 HRC** (typical for corrosion-resistant cavities and cores). * **Tensile Strength:** 1600 – 1950 MPa (232,000 – 283,000 psi) at 50 HRC. * **Impact Toughness:** Good for a stainless tool steel, adequate for mold applications. * **Key Performance Features:** * **Corrosion Resistance:** **Excellent.** Superior to standard tool steels (P20, H13). Highly resistant to rust from condensation, tap water, and acidic decomposition products from plastics like PVC, flame-retardant ABS, and polyacetals. * **Polishability:** **Exceptional (Mirror Class).** The primary advantage of the **ESR process**. The ultra-clean, homogeneous structure allows for the achievement of **flawless, defect-free mirror finishes (SPI #A1)** and perfect replication of fine-etched textures (VDI 3400). * **Dimensional Stability:** Very good during heat treatment, especially when using modern vacuum furnaces. * **Wear Resistance:** Good in the hardened state, suitable for most plastic molding applications. * **Physical Properties:** * **Density:** 7.75 g/cm³ * **Thermal Conductivity:** ~ 24 W/m·K (at 20°C) – Lower than low-alloy steels. * **Coefficient of Thermal Expansion:** ~ 10.5 × 10⁻⁶/°C (20–100°C) * **Modulus of Elasticity:** 200 GPa (29 × 10⁶ psi) ## **5. Product Application** ATI 420 ESR is specified for the highest-end molds where surface finish and corrosion are non-negotiable. * **Optical and Lens Molds:** For cameras, eyewear, LED lenses, and light guides requiring flawless optical surfaces. * **Medical Device Molds:** For syringes, implants, diagnostic equipment, and housings where sterilization, cleanability, and absence of corrosion are mandatory. * **Molds for Corrosive Plastics:** * **Polyvinyl Chloride (PVC)** * **Flame-Retardant (FR) compounds** * **Polyacetals (POM)** * **Consumer Electronics Molds:** For high-gloss housings of mobile phones, laptops, and wearables. * **Food Packaging and Transparent Part Molds:** Where clarity and hygiene are important. * **General High-Polish Molds:** For automotive interior trims and cosmetic packaging. ## **6. Key Features & Advantages of ESR Quality** * **Unmatched Polishability and Texture Transfer:** The **ESR process** ensures an ultra-clean microstructure free from inclusion-related defects, which is the foundation for perfect surface finishes. * **Superior Corrosion Resistance:** High chromium content provides excellent protection in harsh molding environments, extending mold life and reducing maintenance. * **Isotropic Properties:** Uniform mechanical and thermal properties in all directions due to the homogeneous ESR structure, ensuring predictable mold performance. * **Excellent Dimensional Stability:** Minimal and predictable distortion during heat treatment. * **Good Machinability and EDM Performance:** In the annealed or prehardened state, it offers good workability. * **Weldability:** Can be repaired using matching stainless filler rods with proper procedures (pre-heat, post-weld temper). * **Nitriding Suitability:** Responds well to surface hardening treatments like nitriding to further increase surface hardness (>1000 HV) for wear resistance. ## **7. Processing Guidelines** * **Machining:** Use standard tooling for tool steels. In hardened state, use carbide tools. * **Polishing:** Follow sequential grit progression. The material's cleanliness allows for efficient polishing to the highest grades. * **Heat Treatment:** **Always use vacuum or protective atmosphere furnaces** to prevent decarburization and oxidation, which would ruin polishability. * **Welding:** Use matching (420-type) or overalloyed (e.g., 316L) filler metals. Apply pre-heat (200-300°C) and post-weld tempering. * **Storage:** Keep machined surfaces oiled or in low-humidity conditions to leverage its corrosion resistance. **Summary:** ATI Allegheny Ludlum 420 ESR Tool Steel represents the pinnacle of stainless mold steel technology. By applying the Electro-Slag Remelting process to the classic AISI 420 composition, ATI delivers a material with unparalleled internal cleanliness and consistency. This directly translates to the ability to produce optical-quality surface finishes and exceptional corrosion resistance—the two most critical properties for high-end plastic injection molds. For molders in the medical, optical, consumer electronics, and corrosive plastics sectors, 420 ESR is not just a material choice but a strategic investment in mold longevity, part quality, and production reliability. It is the definitive solution where surface perfection and environmental resistance are paramount. -:- For detailed product information, please contact sales. -: ATI Allegheny Ludlum 420ESR Tool Steel, UNS S42000 Specification Dimensions Size： Diameter 20-1000 mm Length <7052 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. -: ATI Allegheny Ludlum 420ESR Tool Steel, UNS S42000 Properties -:- For detailed product information, please contact sales. -:

Applications of ATI Allegheny Ludlum 420ESR Tool Steel Sheet,Plate, UNS S42000 -:- For detailed product information, please contact sales. -: Chemical Identifiers ATI Allegheny Ludlum 420ESR Tool Steel Sheet,Plate, UNS S42000 -:- For detailed product information, please contact sales. -:

Packing of ATI Allegheny Ludlum 420ESR Tool Steel Sheet/Plate, UNS S42000 -:- 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 3523 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