Iron Rod/Bar MIL-I-24137 Class A

Ductile Iron Rod MIL-I-24137 Class A Product Information -:- For detailed product information, please contact sales. -: Ductile Iron Rod MIL-I-24137 Class A Synonyms -:- For detailed product information, please contact sales. -:

Ductile Iron MIL-I-24137 Class A Product Information -:- For detailed product information, please contact sales. -: ### **Product Technical Data Sheet: Ductile Iron – MIL-I-24137 Class A (Ferritic Grade)** --- #### **1. Product Overview** **MIL-I-24137 Class A** is a **high-ductility, ferritic ductile iron** specification established by the United States Military for demanding defense and aerospace applications. This specification has been **cancelled for new design** (as noted by the "CANCELLED" marking in the ASSIST database) but remains a relevant and specified material for legacy systems, maintenance, repair, and overhaul (MRO), and in commercial applications where its guaranteed properties are required. Class A represents the **most ductile grade** within this military standard, emphasizing **toughness, impact resistance, and pressure integrity** over raw strength. It is typically supplied in the fully annealed (ferritized) condition and is analogous to commercial grades like ASTM A536 60-40-18. --- #### **2. Governing Standards & Specifications** This material is defined by a rigorous military performance specification, with clear linkages to commercial standards. * **Primary Standard: MIL-I-24137 (SUPERSEDED / CANCELLED)** - *Iron Castings, Ductile*. The active specification is **MIL-DTL-24137**, but Class A properties remain defined by the original MIL-I document. Users must verify the latest revision and status for contract purposes. * **Cross-Equivalencies & References:** * **ASTM A536:** **Grade 60-40-18** is the direct commercial equivalent. * **SAE J434c:** **Grade D4018**. * **AMS 5312C:** Aerospace Material Specification for "Ductile Iron Castings, Ferritic". * **Federal Standard QQ-I-1104:** Superseded by MIL-I-24137 but historically related. * **Key Testing Standards (as invoked by the MIL spec):** * **Tensile Test:** ASTM E8 * **Hardness:** ASTM E10 (Brinell) * **Impact Test:** ASTM E23 (Charpy) * **Microstructure:** ASTM A247 * **Quality Assurance:** Mandatory compliance with **MIL-STD-453** for inspection and rigorous **first-article and lot testing**. --- #### **3. Chemical Composition Requirements** MIL-I-24137 Class A specifies chemical ranges to ensure a fully ferritic matrix and high nodularity. | Element | MIL-I-24137 Class A Requirement (%) | Functional Rationale | | :--- | :--- | :--- | | **Carbon (C)** | 3.40 - 3.80 | Ensures castability and graphite formation. | | **Silicon (Si)** | 2.20 - 2.60 | Ferritizer. Promotes the soft, ductile ferritic matrix. | | **Manganese (Mn)** | **≤ 0.40** | Strictly limited to prevent pearlite stabilization and boundary segregation, which harms toughness. | | **Phosphorus (P)** | **≤ 0.05** | Kept low to prevent brittle phosphide networks at grain boundaries. | | **Sulfur (S)** | **≤ 0.02** | Kept very low to avoid interference with nodulization. | | **Magnesium (Mg)** | Residual | Sufficient to ensure spheroidal graphite (typically 0.03-0.05%). | | **Copper (Cu)** | **≤ 0.20** | Minimized, as it promotes pearlite, which reduces ductility. | | **Chromium (Cr)** | **≤ 0.10** | Strictly limited as a strong carbide former. | | **Nickel (Ni)** | Report | Not an intentional addition for this class. | | **Other Elements** | As agreed | Trace elements controlled to prevent embrittlement. | --- #### **4. Physical & Mechanical Properties** The properties define a high-toughness, pressure-retaining material. | Property | MIL-I-24137 Class A Requirement | Notes & Significance | | :--- | :--- | :--- | | **Tensile Strength, min.** | **414 MPa (60,000 psi)** | Base strength requirement. | | **Yield Strength (0.2% offset), min.** | **276 MPa (40,000 psi)** | Ensures resistance to permanent deformation. | | **Elongation, min.** | **18%** (in 2 inches) | **Key characteristic:** High ductility, critical for absorbing shock and deformation without fracture. | | **Reduction of Area, min.** | Not typically specified in MIL-I-24137, but implied high. | Further indicator of ductility. | | **Hardness (Brinell)** | **143 - 187 HBW** | Specified range guarantees the soft, ferritic microstructure and excellent machinability. | | **Impact Resistance (Charpy V-Notch)** | **≥ 16 J (12 ft-lbf) @ 21°C (70°F)** | **Critical for military applications.** Guaranteed minimum toughness for shock-loaded components. | | **Modulus of Elasticity** | ~165 - 172 GPa (Assumed) | Consistent with ferritic ductile iron. | | **Microstructure** | **Spheroidal Graphite** (Nodularity ≥85%, Types I & II) in a **predominantly ferritic matrix** (≥90% ferrite). | The ferritic matrix is mandatory for achieving the elongation and impact properties. | --- #### **5. Product Applications** Originally designed for high-reliability military systems, its applications are in areas where failure due to brittle fracture is unacceptable. * **Armored Vehicles:** **Wheel hubs, final drive housings, suspension components, and hull attachments** where mine blast or ballistic shock loads are possible. * **Naval & Marine:** **Valve bodies, pump casings, and fittings** for shipboard piping systems requiring pressure integrity and corrosion resistance. * **Aerospace/Ground Support:** **Landing gear components (non-primary structure), engine mounts, and hydraulic actuator bodies** for support equipment. * **Ordnance & Weapon Systems:** **Housings, mounts, and traversing mechanisms** where shock from firing is a design factor. * **Commercial MRO:** **Replacement parts for legacy military equipment, and in industries** (e.g., power generation, heavy machinery) that adopted this spec for its guaranteed toughness. --- #### **6. Fabrication & Quality Assurance Notes** * **Heat Treatment Condition:** **Annealed (Ferritized).** Castings must be heat treated to achieve the fully ferritic microstructure and meet hardness requirements. * **Machinability:** **Excellent.** The soft ferritic matrix allows for high-speed machining, good surface finishes, and extended tool life. * **Weldability:** **Fair, with strict procedures.** Requires pre-heat (315-650°C), use of nickel-iron electrodes (e.g., ENi-CI), and controlled post-weld cooling with stress relief. Used primarily for repair, not fabrication. * **Military Quality Requirements:** Extremely rigorous. * **Certification:** Foundry must provide a **Certificate of Conformance (C of C)** stating compliance with all requirements of the specification. * **Testing:** **Separately cast test bars** (per ASTM A536 practice) from each melt are used for mechanical testing. **Impact testing is mandatory.** * **Inspection:** Subject to **Government Source Inspection** or customer-approved quality assurance representative. **Non-Destructive Testing (NDT)** such as radiography (X-ray) or magnetic particle inspection is often invoked for critical areas. --- #### **7. Ordering & Procurement Information** **Specify:** **"Ductile Iron Castings, MIL-I-24137 Class A, Ferritic Annealed Condition."** **Critical Information to Include:** * **Reference the exact, current revision** of the specification (e.g., MIL-DTL-24137? Verify status). * **Part Drawing & Application.** * **Required Certifications:** C of C and full test reports (chemistry, tensile, hardness, impact, microstructure). * **Inspection Requirements:** Source inspection requirements, any additional NDT (e.g., per NAVSEA, or drawing callouts). * **Marking:** Requirement for casting marking with material class, foundry identification, and heat number. **Disclaimer:** MIL-I-24137 Class A is a historical specification. For new designs, engineers are directed to use active commercial (ASTM A536) or aerospace (AMS) specifications. However, for sustainment of legacy systems, it remains a vital and precisely defined material standard. -:- For detailed product information, please contact sales. -: Ductile Iron MIL-I-24137 Class A Specification Dimensions Size： Diameter 20-1000 mm Length <6528 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. -: Ductile Iron MIL-I-24137 Class A Properties -:- For detailed product information, please contact sales. -:

Applications of Ductile Iron Rod MIL-I-24137 Class A -:- For detailed product information, please contact sales. -: Chemical Identifiers Ductile Iron Rod MIL-I-24137 Class A -:- For detailed product information, please contact sales. -:

Packing of Ductile Iron Rod MIL-I-24137 Class A -:- 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 2999 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