Alloy A-286,Incoloy A-286,,E FORU

### **Alloy A-286 / Incoloy A-286 (UNS S66286) - Product Introduction** **Overview** **Incoloy A-286** (commonly known as Alloy A-286 and designated UNS S66286) is a premier iron-nickel-chromium superalloy renowned for its high strength and excellent corrosion resistance at elevated temperatures, typically up to about 700°C (1300°F). Unlike many other austenitic stainless steels, A-286 is a **precipitation-hardening** alloy. This means it can be heat treated (solution annealed and aged) to achieve significantly higher strength levels than similar non-hardenable alloys like Type 310 or Alloy 330. Its combination of high tensile and creep strength, good oxidation resistance, and satisfactory fabrication characteristics has made it a standard material for high-stress fasteners and turbine engine components for decades. --- #### **1. Chemical Composition** The chemical composition (in weight %) is precisely balanced to facilitate precipitation hardening. | Element | Content (%) | Role & Benefit | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | The base element of the alloy. | | **Nickel (Ni)** | 24.0 - 27.0 | Stabilizes the austenitic (face-centered cubic) matrix and provides base corrosion resistance. | | **Chromium (Cr)** | 13.5 - 16.0 | Confers resistance to oxidation and corrosion. | | **Molybdenum (Mo)** | 1.0 - 1.5 | Provides solid solution strengthening and enhances creep strength. | | **Titanium (Ti)** | 1.9 - 2.4 | **Critical element.** Forms the primary strengthening precipitate, gamma prime (Ni₃Ti, γ'), during the aging heat treatment. | | **Aluminum (Al)** | ≤ 0.35 | Aids in the formation of the gamma prime (γ') strengthening phase. | | **Vanadium (V)** | 0.10 - 0.50 | Contributes to strength. | | **Boron (B)** | 0.001 - 0.010 | Enhances creep strength by segregating to grain boundaries. | | **Carbon (C)** | ≤ 0.08 | Contributes to strength through carbide formation. | | **Manganese (Mn)** | ≤ 2.00 | Aids in deoxidation during melting. | | **Silicon (Si)** | ≤ 1.00 | Improves resistance to oxidation. | | **Sulfur (S)** | ≤ 0.030 | Impurity element, controlled to improve hot workability. | *Note: "Incoloy" is a registered trademark of Special Metals Corporation (now part of Haynes International). "Incoloy A-286" is their specific brand of this alloy.* --- #### **2. Physical Properties** These properties are essential for engineering design, especially in thermal applications. | Property | Typical Value | | :--- | :--- | | **Density** | 7.93 g/cm³ (0.286 lb/in³) | | **Melting Range** | 1370 - 1425 °C (2500 - 2600 °F) | | **Specific Heat (20°C)** | 460 J/kg·K | | **Thermal Conductivity** | 14.0 W/m·K (at 100°C) | | **Mean Coefficient of Thermal Expansion (20-100°C)** | 15.2 μm/m·°C | | **Modulus of Elasticity (Tensile)** | 201 GPa (29.2 x 10⁶ psi) | | **Magnetic Permeability (Solution Annealed)** | Essentially non-magnetic | --- #### **3. Mechanical Properties** The key advantage of A-286 is its high strength achieved through heat treatment. Typical properties in the **solution annealed and aged condition** are: **Room Temperature Properties (Aged):** | Property | Typical Value | | :--- | :--- | | **Tensile Strength** | 900 - 1100 MPa (130 - 160 ksi) | | **Yield Strength (0.2% Offset)** | 650 MPa (95 ksi) min. | | **Elongation (in 2 inches / 50mm)** | 15% min. | | **Hardness (Rockwell C)** | 28 - 38 HRC | **Elevated Temperature Strength:** A-286 retains excellent strength up to ~700°C (1300°F), with a typical 0.2% yield strength of around 480 MPa (70 ksi) at 650°C (1200°F). It also exhibits good creep and stress-rupture properties. --- #### **4. Product Applications** Incoloy A-286 is widely used in aerospace and industrial applications requiring high strength at elevated temperatures. * **Aerospace & Gas Turbine Engines:** * Turbine and compressor disks (especially in early jet engines). * Turbine blades, spacers, and cases. * Bolts, nuts, studs, and other high-temperature fasteners (its most common modern application). * Afterburner components. * **Automotive Industry:** * Turbocharger components (such as nuts and bolts). * High-performance engine valves and racing exhaust systems. * **Industrial Gas Turbines:** Bolting, structural components, and hot-section parts. * **Nuclear Power:** Fastener applications where a combination of strength and corrosion resistance is needed. * **General Industrial:** High-strength components for high-temperature processing equipment. --- #### **5. International Standards** Alloy A-286 (UNS S66286) is covered by numerous international and industry-specific standards. | Product Form | Standard Specification | | :--- | :--- | | **Bar, Rod, and Wire** | ASTM A453 / ASME SA453 (Grade 660), AMS 5731, AMS 5732, AMS 5737 | | **Forgings** | ASTM A453 / ASME SA453, AMS 5735 | | **Plate, Sheet, and Strip** | ASTM A453 / ASME SA453, AMS 5525, AMS 5871 | | **Seamless Pipe and Tube** | ASTM A213 / ASME SA213 | | **Fastener Specifications** | ASTM A453 / ASME SA453 (Grade 660), AMS 5734 | | **European Material Designation** | **EN 1.4980** (X5NiCrTi26-15) | --- **Summary** **Incoloy A-286 (Alloy A-286 / UNS S66286)** is a classic, precipitation-hardenable superalloy that effectively bridges the gap between stainless steels and more expensive nickel-base superalloys. Its ability to be heat treated to high strength levels while maintaining good oxidation resistance and fabricability makes it an enduring and essential material. Governed by stringent standards like ASTM and aerospace (AMS) specifications, it remains a first-choice material for high-stress, high-temperature applications, most notably as fasteners and critical components in aerospace turbines and other demanding thermal environments.

Packing of Standard Packing: 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 1706 gallon liquid totes Special package is available on request.