Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod/Bar

Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod Product Information -:- For detailed product information, please contact sales. -: Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod Synonyms -:- For detailed product information, please contact sales. -:

Class I Type C Ni-Cr-GB Martensitic White Cast Iron Product Information -:- For detailed product information, please contact sales. -: ## **Product Introduction: Class I Type C Ni-Cr-GB Martensitic White Cast Iron** Class I Type C Ni-Cr-GB Martensitic White Cast Iron is a specialized, high-performance alloy within the ASTM A532 abrasion-resistant iron family, designed to deliver an optimized balance between wear resistance and moderate ductility under impact. The "GB" designation signifies a **Graphite-Bearing** microstructure, achieved through controlled additions of elements like silicon. This intentional formation of a small amount of finely dispersed, spheroidal graphite within an otherwise martensitic, carbide-rich matrix introduces a unique energy-absorbing mechanism, providing improved resistance to crack propagation and thermal shock compared to fully white (non-graphitic) grades. It is engineered for applications where severe abrasion is accompanied by high impact loads, thermal cycling, or where a degree of machinability is required post-casting. This grade represents a sophisticated metallurgical compromise, offering a blend of properties that bridges the gap between traditional white irons and ductile irons in specific high-wear, high-stress applications. --- ### **1. Chemical Composition** The composition is carefully formulated to promote the formation of a small, controlled volume of graphite nodules within a hardenable martensitic white iron matrix. **Typical Composition Range (ASTM A532 Class I Type C - Ni-Cr-GB):** | Element | Content (%) | Primary Function | | :--- | :--- | :--- | | **Chromium (Cr)** | **1.4 - 4.0** | **Carbide former and matrix hardener.** Forms hard (Fe,Cr)₇C₃ carbides for abrasion resistance. Provides solid solution strengthening and moderate oxidation/corrosion resistance. | | **Nickel (Ni)** | **3.3 - 5.0** | **Primary austenite stabilizer and hardenability agent.** Ensures martensite formation upon air quenching by suppressing pearlite transformation, even in the presence of graphite-forming elements. | | **Carbon (C)** | **2.8 - 3.6** | **Dual-role element.** A portion combines with chromium to form hard carbides; the remainder, influenced by silicon, precipitates as fine graphite nodules. The total carbon is high to supply both phases. | | **Silicon (Si)** | **1.5 - 2.5** | **Critical graphite-forming agent.** Higher than in Types A and B to promote the controlled nucleation of graphite nodules. It is a potent ferritizer and deoxidizer. | | **Manganese (Mn)** | 0.5 - 1.5 | Aids in deoxidation and works with Ni to ensure sufficient hardenability for martensite formation. | | **Molybdenum (Mo)** | 0 - 1.0 (Optional) | Added to enhance hardenability, particularly in thicker sections, and to refine the martensitic matrix. | | **Copper (Cu)** | 0 - 1.2 (Optional) | May be used to supplement hardenability and improve atmospheric corrosion resistance. | | **Magnesium (Mg)** | **Trace (0.02 - 0.05)** | Essential for nodularizing the graphite, ensuring it forms as small, isolated spheroids rather than flakes, which would severely weaken the matrix. | | **Iron (Fe)** | Balance | Base metal. | **Microstructural Note:** After a tailored heat treatment (destabilization followed by air cooling), the target microstructure is a **hard martensitic matrix** containing **20-30% volume of chromium-rich carbides (M₇C₃)** and **2-8% volume of fine, well-nodularized graphite (Type VI)**. The graphite nodules are uniformly dispersed and act as crack arrestors and stress relievers. --- ### **2. Physical & Mechanical Properties** The properties reflect a hybrid nature, combining high hardness with improved damage tolerance. | Property | Typical Value / Description | | :--- | :--- | | **Microstructure (Heat-Treated)** | **Martensitic matrix + Chromium carbides + Spheroidal Graphite.** | | **Density** | ~7.4 - 7.6 g/cm³ (Slightly lower than white irons due to graphite). | | **Macrohardness** | **500 - 600 HB** (52 - 58 HRC) – High, but slightly lower than Type A due to the presence of soft graphite. | | **Compressive Strength** | **High** – Maintains good load-bearing capacity. | | **Tensile Strength** | **Moderate (450 - 650 MPa)** – Higher than standard white irons due to the matrix continuity provided by graphite nodules. | | **Yield Strength** | Not typically a primary specification. | | **Elongation** | **Low but measurable (1 - 3%).** A significant improvement over white irons (0%), owing to the graphite's ability to blunt cracks and absorb energy. | | **Fracture Toughness** | **Good for a wear iron (~25-35 MPa√m).** Superior to Types A and B. Graphite nodules impede crack propagation, enhancing resistance to chipping and spalling. | | **Impact Resistance (Charpy Unnotched)** | **20 - 40 J** – The best among Class I martensitic white irons, suitable for high-impact applications. | | **Thermal Shock Resistance** | **Very Good.** The graphite phase provides a degree of thermal conductivity and stress relief, reducing susceptibility to cracking from rapid temperature changes. | | **Abrasion Resistance** | **Very Good.** While the soft graphite nodules can be preferential wear sites in pure abrasion, the hard martensitic matrix and carbides dominate the wear performance, making it highly resistant to gouging and grinding wear. | | **Machinability** | **Poor but improved.** Can be machined with very hard tooling (e.g., carbide) for limited operations like drilling or milling, unlike other white irons which are grind-only. | --- ### **3. Key Product Advantages & Characteristics** * **Enhanced Damage Tolerance:** The graphite nodules act as internal "crack stoppers," significantly improving resistance to crack initiation and propagation under impact, leading to better resistance to chipping and spalling. * **Good Thermal Shock Resistance:** Suitable for applications involving intermittent heating and cooling. * **Improved Machinability:** Allows for post-casting machining for features that are difficult or expensive to cast, such as bolt holes or precise mounting surfaces. * **Good Combination of Strength and Wear Resistance:** Offers a more robust mechanical performance profile than standard white irons while retaining excellent abrasive wear characteristics. --- ### **4. Product Applications** This material is specified for complex, high-value wear parts where pure hardness must be balanced against the risk of brittle fracture. * **Mining & Mineral Processing:** **Pump casings and impellers** for highly abrasive slurries, **cyclone liners**, classifier wear shoes, and components in heavy-media separation systems. * **Power Generation:** Coal pulverizer components (grinding rings, segments) subject to thermal cycling and impact. * **Cement Industry:** Roller press segments, vertical mill grinding elements, and high-wear fan blades. * **Steel & Foundry Industry:** **Shot blasting machine impellers and blades**, liners for abrasive material handling. * **Dredging & Excavation:** Pump volutes and wear plates where impact from rocks is combined with abrasive sand wear. --- ### **5. International Standards** Class I Type C is a distinct grade under the primary ASTM standard, though its unique graphite-bearing nature means exact equivalents in other standards are less common. | Standard | Title / Scope | Common Designations / Notes | | :--- | :--- | :--- | | **ASTM A532/A532M** | *Standard Specification for Abrasion-Resistant Cast Irons* | **Class I Type C** is the definitive standard for Ni-Cr-GB martensitic white iron. The standard provides the required chemical ranges and typical properties. | | **ISO 21988** | *Abrasion-resistant cast irons* | May cover similar materials under "graphite-containing abrasion-resistant cast irons," but a direct Type C equivalent is not explicitly named. | | **Proprietary/Allied Standards** | Often known as **"Abrasion-Resisting Ductile Iron (ARDI)"** or **"Martensitic Nodular White Iron."** | These are commercial or foundry-specific terms for materials with similar graphite-bearing, martensitic, high-hardness microstructures. They may not exactly match the ASTM Type C composition but serve in similar applications. | | **JIS G5511** | *Abrasion-resistant white cast irons* (Japanese) | Does not include graphite-bearing grades. | | **DIN EN 12513** | *Founding - Abrasion resistant cast irons* (European) | Focuses on white irons; graphite-containing abrasion-resistant grades are a separate category. | **Specification Note:** Procurement requires clear specification of **"ASTM A532, Class I Type C."** Given its hybrid nature, additional requirements are often critical: * **Microstructural Analysis:** Specification of **minimum nodularity** (e.g., >80% nodular graphite) and **maximum allowed graphite volume fraction** (e.g., 5% max). * **Mechanical Tests:** Minimum hardness and often a **minimum Charpy impact value** to ensure the desired toughness is achieved. * **Soundness Requirements:** Strict non-destructive testing (NDT) to ensure the graphite does not cluster in a way that creates weakness. --- ### **Conclusion** Class I Type C Ni-Cr-GB Martensitic White Cast Iron is a sophisticated, hybrid alloy that successfully integrates the **wear-defying hardness of chromium carbides and martensite** with the **crack-arresting capability of nodular graphite**. This unique structure grants it superior **fracture toughness, impact resistance, and thermal shock behavior** compared to its fully white counterparts in Class I. While its pure abrasion resistance may be marginally lower, its overall **service life in complex, high-stress wear environments**—particularly those involving impact, thermal cycles, or the need for machinability—is often significantly extended. It stands as a testament to advanced metallurgical design, providing a tailored solution where conventional white irons are too brittle and tougher materials lack sufficient wear resistance. -:- For detailed product information, please contact sales. -: Class I Type C Ni-Cr-GB Martensitic White Cast Iron Specification Dimensions Size： Diameter 20-1000 mm Length <6491 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. -: Class I Type C Ni-Cr-GB Martensitic White Cast Iron Properties -:- For detailed product information, please contact sales. -:

Applications of Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod -:- For detailed product information, please contact sales. -: Chemical Identifiers Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod -:- For detailed product information, please contact sales. -:

Packing of Class I Type C Ni-Cr-GB Martensitic White Cast Iron Rod -:- 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 Rod 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 2962 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