Latrobe,Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil/Strip

Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil Product Information -:- For detailed product information, please contact sales. -: Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil Synonyms -:- For detailed product information, please contact sales. -:

Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Product Information -:- For detailed product information, please contact sales. -: # **Product Datasheet: Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel** ## **Executive Summary** Latrobe Lescalloy® **D6AC VAC-ARC** is a premier **air-hardening, medium-carbon, high-strength alloy steel** refined through the **Vacuum Arc Remelting (VAR)** process. Renowned for its exceptional combination of **high strength, good toughness, and deep hardenability**, D6AC has served as a benchmark material for critical, high-stress components in aerospace and defense for decades. The **VAC-ARC remelting** significantly enhances its purity, fatigue life, and fracture toughness compared to its air-melted counterpart, making it the preferred choice for the most demanding applications. --- ## **Material Technology & Processing** **Metallurgical Foundation:** D6AC is a versatile **chromium-molybdenum-vanadium steel** that achieves its properties through a martensitic transformation. The **VAR process** provides key advantages: - **Reduced Gas Content:** Lowers oxygen, hydrogen, and nitrogen to minimize inclusion content and improve ductility. - **Improved Homogeneity:** Creates a more uniform chemical and microstructural distribution. - **Enhanced Cleanliness:** Results in superior fatigue resistance and better transverse mechanical properties. - **Consistent Hardenability:** Ensures reliable performance in varying section sizes. **Heat Treatment Flexibility:** D6AC can be processed through multiple heat treatment routes to tailor properties for specific applications, including oil quenching and austempering. --- ## **Chemical Composition (Typical Weight %)** *Conforms to standard D6AC with tight compositional control enabled by VAR.* | Element | Content Range (%) | Metallurgical Function | |---------|------------------|------------------------| | **Carbon (C)** | 0.42 - 0.48 | Primary strengthening; forms hard martensite and carbides | | **Chromium (Cr)** | 0.90 - 1.20 | Increases hardenability, wear resistance, and high-temperature strength | | **Molybdenum (Mo)** | 0.90 - 1.10 | Enhances hardenability, strength, and reduces temper embrittlement | | **Vanadium (V)** | 0.07 - 0.13 | Forms fine, stable carbides for grain refinement and secondary hardening | | **Manganese (Mn)** | 0.60 - 0.90 | Increases hardenability and strength | | **Silicon (Si)** | 0.15 - 0.30 | Deoxidizer and solid solution strengthener | | **Nickel (Ni)** | 0.40 - 0.70 (Optional/Residual) | Improves toughness, often specified for critical applications | | **Sulfur (S)** | ≤ 0.010 | Minimized for improved transverse ductility and toughness | | **Phosphorus (P)** | ≤ 0.010 | Minimized to prevent embrittlement | | **Iron (Fe)** | Balance | Matrix | --- ## **Physical & Mechanical Properties** ### **Typical Mechanical Properties (After Oil Quench & Temper)** | Property | Value Range | Units | Condition / Note | |----------|-------------|--------|------------------| | **Tensile Strength** | 220 - 260 | ksi (1517 - 1793 MPa) | Varies with tempering temperature | | **0.2% Yield Strength** | 195 - 230 | ksi (1345 - 1586 MPa) | | | **Elongation (in 2")** | 10 - 14 | % | | | **Reduction in Area** | 35 - 50 | % | | | **Hardness** | 50 - 56 | HRC | Dependent on tempering | | **Fracture Toughness (K_Ic)** | 70 - 110 | ksi√in (77 - 121 MPa√m) | Superior to air-melted D6AC due to VAR | ### **Hardenability Data (Jominy Test Typical)** - Excellent depth of hardening due to Cr-Mo synergy. - Capable of achieving full martensitic structure in sections up to approximately **4 inches (100 mm)** in diameter when oil quenched. ### **Physical Constants** | Property | Value | Units | |----------|-------|--------| | **Density** | 0.284 | lb/in³ (7.86 g/cm³) | | **Modulus of Elasticity** | 29.0 x 10⁶ | psi (200 GPa) | | **Poisson's Ratio** | 0.29 | | | **Thermal Conductivity** | 21.2 | BTU·in/(hr·ft²·°F) at 212°F | | **Coefficient of Thermal Expansion** | 6.3 x 10⁻⁶ | /°F (68-600°F range) | --- ## **International Standards & Specifications** Latrobe Lescalloy D6AC VAC-ARC is produced to meet the most stringent international and industry specifications. ### **Primary Aerospace & Defense Specifications** - **AMS 6431:** Steel Bars, Forgings, and Tubing, 0.45C - 1.0Cr - 1.0Mo - (0.08V) (D6AC) - **MIL-S-8949 (Amended):** Secondary Hardening Steel Plate (D6AC composition) - **ASTM A579/A579M:** Standard Specification for Superstrength Alloy Steel Forgings (often references D6AC-type steels) ### **Customer-Specific & Proprietary Standards** - **Boeing BAC 5601, BAC 5613** - **Northrop Grumman Specifications** - **Lockheed Martin Specifications** - **Latrobe Internal Premium Quality (PQ) Specifications** for VAR material ### **Quality & Testing Compliance** - **AMS 2301:** Premium Aircraft-Quality Steel Cleanliness (Fineness Rating A or better) - **AMS 2304:** Detection of Soft Carburization and Decarburization - **ASTM E45:** Standard Test Methods for Determining the Inclusion Content of Steel - **ASTM E1019:** Standard Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel --- ## **Product Applications** D6AC VAC-ARC is specified for highly stressed, fracture-critical components where reliability is paramount. ### **Aerospace (Iconic Application)** - **Solid Rocket Motor Casings:** Historically used for Space Shuttle SRBs and other launch vehicles; high strength-to-weight ratio is critical. - **Aircraft Landing Gear:** Major structural components (beams, pistons, trunnions) for military and commercial aircraft. - **Airframe Components:** Wing carry-through structures, engine mounts, and critical fittings. - **Helicopter Components:** Rotor hubs, drive shafts, and landing gear. ### **Defense & Ordnance** - **Armor Components** for light and medium armored vehicles. - **Gun Components:** Recoil cylinders, breech rings, and other high-pressure vessel applications. - **Missile & Rocket Bodies.** ### **High-Performance Industrial** - **High-Stress Tools and Dies.** - **Oil & Gas Drilling Components:** Heavy-duty parts requiring high strength and good fatigue resistance. - **High-Performance Racing Components:** Suspension parts and drivetrain components. --- ## **Manufacturing & Fabrication Guidelines** ### **Recommended Heat Treatment** 1. **Preheat:** 1200-1300°F (649-704°C) to minimize thermal stress. 2. **Austenitize:** 1575-1625°F (857-885°C), soak time dependent on section size. 3. **Quench:** Agitated oil quench is standard; can be air-cooled for suitable sections (air-hardening characteristic). 4. **Temper:** Immediately after quenching. Temper between **500-1100°F (260-593°C)** to achieve desired strength/toughness balance. Double tempering is often recommended. ### **Machining & Fabrication** - **Annealed Condition:** Hardness ~ 255 HB (26 HRC). Machinability is fair; requires appropriate tooling and speeds. - **Hardened Condition:** Machining is difficult; grinding or EDM is typically required. - **Welding:** Weldable with extreme caution. Requires: - Preheating (400-600°F / 204-316°C) - Use of low-hydrogen, high-nickel welding electrodes (e.g., ENiCrFe-type) - Strict post-weld heat treatment (PWHT) to restore properties and relieve stresses - 100% non-destructive testing (NDT) ### **Quality Assurance** - **Melting Report:** Full traceability including VAR remelt log. - **Ultrasonic Testing:** Per customer requirements (typically AMS-STD-2154). - **Mechanical Testing:** Longitudinal and transverse tests from representative locations. - **Macro/Micro Cleanliness:** Per AMS 2301 or equivalent. --- ## **Available Product Forms & Sizes** - **Primary Forms:** Forged and rolled bars, forged billets, rings, and near-net-shape forgings. - **Size Range:** Diameters/Thickness from 1 inch up to ~30 inches (25 mm - 760 mm) depending on form. - **Condition:** Annealed, rough machined, or heat treated per print. --- ## **Technical Support** Latrobe provides in-depth technical support for D6AC VAC-ARC, including: - Application-specific heat treatment cycle development. - Welding procedure specification (WPS) qualification support. - Forging and processing recommendations. - Failure analysis and component life assessment. --- **Disclaimer:** This datasheet provides characteristic information. For design and procurement, consult official Latrobe Specialty Metals technical data sheets and engage with their application engineering team. Properties are dependent on exact processing parameters. This material may be subject to export control regulations. -:- For detailed product information, please contact sales. -: Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6457 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. -: Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil -:- For detailed product information, please contact sales. -: Chemical Identifiers Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil -:- For detailed product information, please contact sales. -:

Packing of Latrobe Lescalloy® D6AC VAC-ARC High Strength Alloy Steel Foil/Strip -:- 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 Foil/Strip 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 2928 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