Assab Steels 618 Plastic Mold Material

Assab Steels 618 Plastic Mold Material Product Information -:- For detailed product information, please contact sales. -: Assab Steels 618 Plastic Mold Material Synonyms -:- For detailed product information, please contact sales. -:

Assab Steels 618 Plastic Mold Material Product Information -:- For detailed product information, please contact sales. -: ### **Assab Steels 618: Versatile and High-Quality P20-Type Plastic Mold Steel** --- #### **1. Introduction** **Assab Steels 618** is a premium-grade, chromium-molybdenum (Cr-Mo) alloyed **plastic mold steel** belonging to the P20 family. It is a versatile, general-purpose mold steel known for its excellent balance of machinability, polishability, and uniform hardness in the pre-hardened condition. Supplied ready-to-machine, 618 eliminates the need for costly and time-consuming heat treatment by the mold maker, making it a cost-effective and reliable choice for a wide range of injection molds and other tooling applications. **Key Value Propositions:** * **Excellent Machinability:** Offers superior cutting performance in its pre-hardened state, reducing tool wear and machining time. * **Very Good Polishability:** Capable of achieving high-quality surface finishes, suitable for glossy or textured plastic parts. * **Uniform Pre-Hardened Structure:** Supplied at a consistent hardness throughout the entire cross-section, ensuring predictable performance and minimal distortion during machining. * **Good Weldability:** Allows for mold repairs and modifications using standard welding techniques with appropriate procedures. * **Consistency & Reliability:** Manufactured under strict quality control to ensure homogeneous properties and reliable performance in every batch. * **Wide Availability:** One of the most widely used and readily available premium P20-type steels globally. --- #### **2. International Standard Designations** * **Assab / Uddeholm:** 618 * **AISI / ASTM A681:** P20 Modified / Premium Quality * **European Norm (EN):** 1.2312 (40CrMnMo7) * **DIN:** 40CrMnMo7 (1.2312) * **JIS:** PDS5 * **GB (China):** 3Cr2Mo --- #### **3. Chemical Composition (Typical Weight %)** | Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Chromium (Cr) | Molybdenum (Mo) | | :--- | :---: | :---: | :---: | :---: | :---: | | **%** | 0.40 | 0.30 | 1.50 | 1.90 | 0.20 | *Note: This balanced composition provides good hardenability, strength, and polishability without excessive alloying cost.* --- #### **4. Physical & Mechanical Properties (As Supplied - Pre-Hardened)** * **Hardness (Supplied):** **290 - 330 HB** (Approx. **30 - 34 HRC**) * **Tensile Strength:** ~ 1000 - 1150 MPa * **0.2% Proof Strength (Yield Strength):** ~ 800 MPa (min) * **Impact Toughness (Charpy V):** Good, suitable for most mold applications * **Density:** 7.8 g/cm³ * **Thermal Conductivity:** ~ 36 W/m·K (at 20°C) * **Coefficient of Thermal Expansion:** 12.5 x 10⁻⁶/K (20-100°C) --- #### **5. Heat Treatment & Processing** * **Supply Condition:** Pre-hardened and tempered, ready for immediate machining. * **Nitriding / Surface Hardening:** Responds well to gas or plasma nitriding to increase surface hardness (up to 650-700 HV) for enhanced wear resistance in molds processing abrasive plastics. * **Through-Hardening (If Required):** Can be austenitized at 840-870°C, oil quenched, and tempered to higher hardness levels (up to ~52 HRC) for specialized applications, though this is not its primary use case. * **Stress Relieving:** For complex or high-precision molds, stress relieving at 500-550°C after rough machining is recommended. --- #### **6. Product Applications** Assab 618 is the ideal, all-rounder steel for a vast majority of plastic injection molds. 1. **General-Purpose Injection Molds:** * Molds for consumer products, household items, and automotive interiors. * Low to medium-volume production molds. 2. **Molds for Engineering Plastics:** * Suitable for glass-filled materials (with consideration for potential wear; nitriding is recommended for high volumes). 3. **Large Mold Bases and Plates:** * Due to its excellent through-hardening properties, it provides consistent strength in large sections. 4. **Prototype Molds and Tooling:** * Its excellent machinability allows for fast turnaround in mold development. 5. **Molds Requiring Good Surface Finish:** * For textured or glossy parts (e.g., ABS, PP, PS). 6. **Other Tooling:** * Jigs, fixtures, and mechanical components requiring good stability and machinability. --- #### **7. Machining & Fabrication Guide (Pre-Hardened Condition)** | Process | Recommendation | | :--- | :--- | | **Turning** | Use coated carbide tools with positive geometry. Good chip control and surface finish are easily achieved. | | **Milling** | HSS or carbide end mills perform well. Use stable setups and adequate coolant. | | **Drilling** | Standard HSS drills with proper pecking cycles and coolant work effectively. | | **Grinding** | Responds well to grinding with aluminum oxide wheels. Use standard parameters. | | **EDM (Sinker & Wire)** | Excellent performance. A fine, recast layer is formed but is easily polished off. | | **Polishing** | Sequences from coarse diamond stone to fine diamond paste yield very good to excellent surface finishes. | --- #### **8. Quality & Supply Forms** * **Quality:** Vacuum degassed for high purity and homogeneity. Subject to stringent internal quality checks. * **Available Forms:** Supplied in pre-hardened, black or machined condition. * Precision ground flat stock (PGFS) * Blocks and billets * Round and square bars * Custom-sized plates --- #### **9. Comparison: 618 vs. Higher-Grade 718HH** | **Parameter** | **Assab 618** | **Assab 718HH** | | :--- | :--- | :--- | | **Supplied Hardness** | 290-330 HB (30-34 HRC) | **340-380 HB (36-40 HRC)** | | **Primary Advantage** | **Excellent Machinability & Cost-Effectiveness** | **Higher Wear Resistance & Strength** | | **Polishability** | Very Good | **Excellent** | | **Typical Application Scope** | General-purpose, medium-volume molds | High-precision, high-volume, abrasive materials | | **Alloy Content (Ni)** | Standard P20 | **Added Nickel for toughness/hardenability** | --- #### **10. Conclusion** **Assab Steels 618** stands as the cornerstone of reliable plastic mold manufacturing. Its well-rounded properties—outstanding machinability, very good polishability, and consistent pre-hardened quality—make it the default and most economical choice for the majority of injection molding applications. For mold makers seeking a proven, readily available, and easy-to-work-with material that delivers predictable results batch after batch, 618 remains an unbeatable value proposition and a testament to Assab's commitment to foundational quality. -:- For detailed product information, please contact sales. -: Assab Steels 618 Plastic Mold Material Specification Dimensions Size： Diameter 20-1000 mm Length <7245 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. -: Assab Steels 618 Plastic Mold Material Properties -:- For detailed product information, please contact sales. -:

Applications of Assab Steels 618 Plastic Mold Material -:- For detailed product information, please contact sales. -: Chemical Identifiers Assab Steels 618 Plastic Mold Material -:- For detailed product information, please contact sales. -:

Packing of Assab Steels 618 Plastic Mold Material -:- 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 3716 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