Bohler-Uddeholm,M238 VMR® P20 Plastic Lens Mold Steel Flange

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Flange Product Information -:- For detailed product information, please contact sales. -: Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Flange Synonyms -:- For detailed product information, please contact sales. -:

Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Product Information -:- For detailed product information, please contact sales. -: # **Böhler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel** ## **Product Overview** **Böhler-Uddeholm M238 VMR®** is a specialized **pre-hardened, chromium-nickel alloyed plastic mold steel** engineered specifically for the highest-demand optical applications, particularly **precision lens molds and components requiring exceptional surface finishes**. Supplied at a uniform pre-hardened state, this material combines the machinability advantages of P20-type steels with superior internal cleanliness and microstructure control achieved through **VMR® (Vacuum Melted and Remelted)** processing. Its optimized composition and advanced manufacturing ensure **outstanding polishability, excellent etching characteristics, and consistent isotropic properties** critical for producing optical-grade plastic components. --- ## **1. Key Characteristics & Advantages** * **Exceptional Polishability:** Capable of achieving ultra-high mirror finishes (SPI A-0/A-1, #0/#1 Diamond finish) without "orange peel" or pitting defects, essential for optical clarity. * **Superior Microstructural Cleanliness:** VMR® process ensures extremely low sulfur (<0.001%) and non-metallic inclusion content, directly translating to flawless polishing and etching performance. * **Excellent Photochemical Etching (Texturing) Performance:** The homogeneous, clean structure allows for precise, high-resolution texturing with sharp definition and consistency. * **Good Corrosion Resistance:** Provides adequate resistance to moisture and common coolants, protecting the mold surface during production and storage. * **Ready-to-Machine State:** Supplied pre-hardened (~30-33 HRC), eliminating heat treatment and associated distortion risks, while maintaining excellent machinability. * **High Dimensional Stability:** Excellent stability during machining and in service due to uniform properties and stress-relieved condition. * **Isotropic Properties:** Uniform behavior in all directions (longitudinal and transverse), ensuring predictable machining, polishing, and tool performance. --- ## **2. Typical Chemical Composition (Weight %)** | Element | Carbon (C) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Manganese (Mn) | Silicon (Si) | | :--- | :---: | :---: | :---: | :---: | :---: | :---: | | **Content** | **0.20 - 0.25** | **1.40 - 1.60** | **3.80 - 4.20** | **0.15 - 0.25** | **1.40 - 1.60** | **0.20 - 0.40** | **Alloying Rationale:** * **Nickel (4.0%):** The key differentiating element from standard P20. Promotes a tough, fine-grained microstructure with high impact strength and enhances polishability. * **Chromium (1.5%) & Molybdenum (0.2%):** Provide hardenability and strength in the pre-hardened state. * **Low Carbon (0.23%):** Optimized to balance machinability with sufficient hardness, while minimizing carbide banding that can interfere with polishing. * **VMR® Process:** Vacuum melting followed by vacuum arc remelting ensures exceptional purity, homogeneity, and a fine, uniform microstructure—the foundation of its optical-grade performance. --- ## **3. Physical & Mechanical Properties** ### **Physical Properties (at ~31 HRC):** * **Density:** ~7.85 g/cm³ * **Thermal Conductivity:** ~36 W/(m·K) at 20°C * **Modulus of Elasticity:** ~205 GPa * **Coefficient of Thermal Expansion:** ~12.8 x 10⁻⁶/K (20-100°C) ### **Mechanical Properties (Delivery Condition):** * **Hardness:** **290 - 330 HBW (30 - 34 HRC)** * **Tensile Strength:** ~1000 - 1150 MPa * **Yield Strength (0.2% offset):** ~850 - 950 MPa * **Elongation at Break:** ~12-15% * **Impact Strength (Charpy V):** **> 50 J** (Notably higher than standard P20 due to Ni content) * **Machinability Index:** ~85% (Excellent for its hardness level) --- ## **4. Primary Applications** M238 VMR® is exclusively designed for high-precision plastic molds where surface finish quality is paramount. * **Optical Component Molds:** * **Injection molds for precision lenses** (camera, smartphone, VR/AR, projector, microscope lenses). * **Light guides, diffusers, and reflectors** for LED lighting and displays. * **Transparent covers and windows** for medical devices and instruments. * **High-Gloss Surface Molds:** * **Consumer electronics housings** (laptops, tablets, televisions) requiring flawless Class-A surfaces. * **Automotive lens covers** (headlights, taillights, interior lighting). * **Cosmetic packaging** and premium consumer goods. * **Other Precision Components:** Master models, EDM electrodes for fine-featured cavities, and gauges requiring superior surface integrity. --- ## **5. Relevant International Standards & Comparable Grades** M238 is a proprietary Böhler-Uddeholm grade. Its composition aligns with a high-nickel variant within the P20 family but is distinguished by its VMR® quality level. | Standard | Grade / Designation | Country/Region | Similarity / Key Difference | | :--- | :--- | :--- | :--- | | **Proprietary (Böhler-Uddeholm)** | **M238 VMR®** | International | The reference optical-grade, Ni-alloyed P20 steel. | | **AISI / ASTM** | **P20+Ni (Modified)** | USA | Fits the "P20 Modified with Ni" category. M238 defines the premium standard within it. | | **DIN / Werkstoff** | **1.2738 (≈35CrNiMo6)** | Germany/EU | The common pre-hardened mold steel with Ni. M238 VMR® represents the highest quality tier of this classification with guaranteed optical properties. | | **JIS** | **PX5 / NAK55** | Japan | Japanese pre-hardened Ni-Cu-Al age-hardening steels. M238 is a through-hardening Cr-Ni-Mo steel with different metallurgy but similar application target (high polish). | | **Other Proprietary** | **IMPAX® Hi-Hard / SUPREME** | Uddeholm | Other premium pre-hardened steels; M238 is specifically optimized for optical polishability via its VMR® process and controlled chemistry. | **Critical Specification:** For optical applications, specifying **"M238 VMR®"** is essential to guarantee the material cleanliness and consistency required for defect-free high-polish results. --- ## **6. Processing & Fabrication Guidelines** * **Machining:** **Excellent machinability** in its pre-hardened state. Use sharp carbide tools. Its uniform structure provides predictable chip formation and good surface finishes directly from machining. * **Drilling & Tapping:** Performs very well. Standard practices apply. * **Grinding:** Straightforward. Use aluminum oxide wheels with standard parameters and adequate cooling. * **EDM (Sinker & Wire):** Performs exceptionally well due to its homogeneity. The fine, recast layer is typically easy to polish out. A light stress relief at 400-450°C post-EDM can be beneficial for critical optics. * **Polishing:** The core application strength. Begin with fine stone finishing (e.g., #600 grit) and progress systematically through diamond compounds (e.g., 15µm to 1µm or finer). The VMR® structure avoids the inclusion-related defects common in lower-grade steels. * **Photochemical Etching / Laser Texturing:** Delivers excellent, consistent results due to uniform material removal. * **Welding:** Good weldability for a pre-hardened steel. For repairs: * **Pre-heat:** 250 - 300°C. * **Filler Metal:** Use a soft, crack-resistant filler (e.g., AWS ER70S-6 or a proprietary mold repair wire). * **Post-Weld:** Temper immediately at 400 - 450°C and slow cool. * **Surface Hardening:** Can be nitrided to increase surface hardness (~700-900 HV) for enhanced wear resistance on parting lines or runner surfaces, though this is rarely needed for pure optical applications. --- ## **7. Conclusion** **Böhler-Uddeholm M238 VMR®** is not merely a mold steel; it is a **specialized optical manufacturing substrate**. Its development is focused on a single, critical outcome: enabling the production of plastic components with flawless optical surfaces. By integrating nickel alloying for toughness and, most importantly, the VMR® process for ultimate cleanliness, it solves the fundamental challenges of polishing and texturing high-precision molds. For molders of optical lenses, light guides, and any component where surface perfection directly defines product functionality and value, M238 VMR® is the definitive and necessary choice. It transforms the risk of polishing defects into a predictable, high-yield manufacturing process, ensuring that the mold material itself never limits the optical quality of the final part. -:- For detailed product information, please contact sales. -: Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6889 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 M238 VMR® P20 Plastic Lens Mold Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Flange -:- For detailed product information, please contact sales. -: Chemical Identifiers Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Flange -:- For detailed product information, please contact sales. -:

Packing of Bohler-Uddeholm M238 VMR® P20 Plastic Lens Mold Steel Flange -:- 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 Flange 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 3360 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