Haynes 625SQ Nickel Alloy,Haynes 625SQ alloy，1

### **Introduction to Haynes® 625 SQ (Static Quality) Alloy** **Haynes® 625 SQ** is a specialized variant of the renowned nickel-chromium-molybdenum alloy 625, engineered specifically for high-strength, static structural applications. The "SQ" stands for **"Static Quality,"** indicating it is optimized to provide exceptional **strength and stability in non-rotating, non-dynamic components** at elevated temperatures. While standard Alloy 625 is prized for its excellent corrosion resistance and fatigue strength, the 625 SQ version is processed to achieve significantly higher **short-term and long-term tensile and creep-rupture properties**, making it ideal for critical airframe and engine structures. --- ### **Chemical Composition (Weight %, typical)** The composition is fundamentally the same as standard Alloy 625, relying on the solid-solution strengthening effect of molybdenum and niobium. | Element | Minimum | Maximum | Key Function | | :--- | :--- | :--- | :--- | | **Nickel (Ni)** | **Balance** | | Forms the stable austenitic matrix. | | **Chromium (Cr)** | 20.0 | 23.0 | Provides resistance to oxidation and corrosion. | | **Molybdenum (Mo)** | 8.0 | 10.0 | Primary solid-solution strengthener; enhances strength and pitting resistance. | | **Niobium (Nb)** | 3.15 | 4.15 | Forms stable carbides and contributes to solid-solution strengthening. | | **Iron (Fe)** | - | 5.0 | - | | **Aluminum (Al)** | - | 0.40 | - | | **Titanium (Ti)** | - | 0.40 | - | | **Carbon (C)** | - | 0.10 | - | | **Manganese (Mn)** | - | 0.50 | - | | **Silicon (Si)** | - | 0.50 | - | *The key difference lies not in the chemistry, but in the **thermomechanical processing and heat treatment**, which are controlled to maximize strength for static applications.* --- ### **Physical Properties (Typical)** * **Density:** 8.44 g/cm³ (0.305 lb/in³) * **Melting Range:** 1290 - 1350 °C (2350 - 2460 °F) * **Thermal Expansion Coefficient:** 12.8 μm/m·°C (20-100°C) * **Thermal Conductivity:** 9.8 W/m·K at 100°C * **Modulus of Elasticity (Young's Modulus):** 207 GPa (30 x 10⁶ psi) at 21°C --- ### **Mechanical Properties (Typical at Room Temperature)** The mechanical properties of 625 SQ are superior to those of standard, annealed Alloy 625, particularly in terms of strength. | Property | Standard 625 (Annealed) | **625 SQ (Typical)** | | :--- | :--- | :--- | | **Tensile Strength** | ≥ 827 MPa (120 ksi) | **≥ 1034 MPa (150 ksi)** | | **Yield Strength (0.2% Offset)** | ≥ 414 MPa (60 ksi) | **≥ 758 MPa (110 ksi)** | | **Elongation** | ≥ 30% | ≥ 20% | ***High-Temperature Strength:*** The primary advantage of 625 SQ is its retention of this high strength at elevated temperatures (up to ~1200°F / 650°C), offering superior creep-rupture strength compared to the standard grade. --- ### **Key Characteristics and Product Applications** #### **Key Characteristics:** 1. **Enhanced Static Strength:** The primary feature is its high yield and tensile strength, making it suitable for load-bearing structures. 2. **Excellent Creep Resistance:** Performs reliably under sustained mechanical stress and high temperatures, a critical requirement for engine and airframe components. 3. **Good Oxidation Resistance:** Inherits good resistance to oxidation from its high chromium content. 4. **Good Fabricability and Weldability:** It can be welded using standard techniques, though post-weld heat treatment may be required to restore properties in the heat-affected zone. Matching filler metal ERNiCrMo-3 is typically used. #### **Primary Applications:** Haynes 625 SQ is targeted at high-strength, static structural applications, primarily in the aerospace sector. * **Aerospace & Jet Engines:** * **Engine Mounts and Pylons:** Critical structural links between the engine and the airframe. * **Exhaust System Components:** Such as thrust reverser structures and cascade rings. * **Fan Cases and Containment Rings.** * **Airframe Components:** Used in high-temperature areas of the airframe near engines. * **Industrial Gas Turbines:** * Structural casings and supports. --- ### **International Standards** Haynes 625 SQ is typically governed by specific Aerospace Material Specifications (AMS) that call out the required enhanced strength levels. | Product Form | Standard | Designation | Notes | | :--- | :--- | :--- | :--- | | **Bar, Forgings, Ring** | **AMS 5666** (or specific grade) | Alloy 625 | Often supplied to a specific "code" or "grade" within AMS 5666 that guarantees the higher strength properties of 625 SQ. | | **Sheet, Strip, Plate** | **AMS 5599** (or specific grade) | Alloy 625 | Similarly, specific procurement specifications will call out the required SQ-level mechanical properties. | | **Welding Consumables** | AWS A5.14 / AMS 5837 | **ERNiCrMo-3** | The standard matching filler metal for Alloy 625 is used. | **Note:** "Haynes" is a registered trademark of **Haynes International, Inc.** "625 SQ" is a proprietary designation for material meeting specific high-strength requirements. Procurement of 625 SQ must explicitly specify the required mechanical property thresholds, as they are not automatically guaranteed by the standard AMS 5666 or AMS 5599 listings alone.

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 3264 gallon liquid totes Special package is available on request.