Altemp X-750 Nickel-Based superalloy,UNS N07750，1

### **Product Datasheet: Altemp X-750 / Alloy X-750 (UNS N07750)** **A Precipitation-Hardenable Nickel-Chromium Superalloy with High Strength and Good Corrosion Resistance** --- #### **1. Overview** **Altemp X-750**, commonly known as **Alloy X-750**, is a precipitation-hardenable nickel-chromium alloy derived from the classic Alloy 600. It is renowned for its combination of **high strength**, **excellent corrosion resistance**, and **good oxidation resistance** up to approximately 700°C (1300°F). The alloy's key characteristic is its ability to be strengthened by a precipitation hardening (aging) treatment after being solution annealed. This process forms finely dispersed gamma prime (γ') particles, significantly increasing its yield strength. It is a versatile material that maintains good fabricability and weldability in the annealed condition, making it suitable for a wide range of high-stress applications. #### **2. Chemical Composition (Typical Weight %)** The composition is designed for a balance of strength, corrosion resistance, and age-hardening capability. | Element | Content (%) | Role in the Alloy | | :--- | :--- | :--- | | **Nickel (Ni)** | Balance (~70) | Forms the austenitic matrix. | | **Chromium (Cr)** | ~14.0 - 17.0 | Provides oxidation and corrosion resistance. | | **Iron (Fe)** | ~5.0 - 9.0 | Solid solution strengthener and cost-effective matrix element. | | **Titanium (Ti)** | ~2.25 - 2.75 | Forms the primary strengthening γ' phase (Ni₃(Al,Ti)). | | **Aluminum (Al)** | ~0.40 - 1.00 | Forms the primary strengthening γ' phase (Ni₃(Al,Ti)). | | **Niobium + Tantalum (Nb+Ta)** | ~0.70 - 1.20 | Forms the strengthening γ'' phase (Ni₃Nb) and stabilizes carbides. | | **Cobalt (Co)** | ≤ 1.00 | Residual element. | | **Manganese (Mn)** | ≤ 1.00 | Residual element. | | **Silicon (Si)** | ≤ 0.50 | Residual element. | | **Copper (Cu)** | ≤ 0.50 | Residual element. | | **Carbon (C)** | ≤ 0.08 | Forms carbides for grain boundary strength. | | **Sulfur (S)** | ≤ 0.01 | Residual element. | #### **3. Physical Properties (Typical)** | Property | Value / Condition | | :--- | :--- | | **Density** | 8.28 g/cm³ (0.299 lb/in³) | | **Melting Range** | ~1390 - 1430 °C (~2540 - 2610 °F) | | **Thermal Expansion Coefficient** | ~13.9 μm/m·°C (20 - 540°C) | | **Thermal Conductivity** | ~14.0 W/m·K (at 100°C) | | **Modulus of Elasticity** | ~214 GPa (31 x 10⁶ psi) at 20°C | #### **4. Mechanical Properties** Properties vary significantly with heat treatment. The following are representative for bar stock after a standard age-hardening treatment (e.g., AMS 5667). **At Room Temperature (Age-Hardened):** * **Tensile Strength:** > 1030 MPa (150 ksi) * **Yield Strength (0.2% Offset):** > 690 MPa (100 ksi) * **Elongation:** > 20% **At Elevated Temperature (e.g., 650°C / 1200°F):** * Retains a high percentage of its room-temperature strength and offers excellent creep and stress-rupture properties. #### **5. Heat Treatment** Alloy X-750 is typically heat treated in a two-step process: 1. **Solution Treatment:** Heated to approximately 1150°C (2100°F) for a full anneal or 980°C (1800°F) for a mill anneal, followed by rapid cooling. This dissolves the hardening elements. 2. **Aging / Precipitation Hardening:** Several standardized aging treatments are used depending on the application: * **AH (Aging Heat Treatment):** 730°C (1350°F) for 8 hours, furnace cool to 620°C (1150°F) for 8 hours, then air cool. This is common for high-temperature spring applications. * **HTH (Hold Then Harden):** 840°C (1550°F) for 24 hours, air cool, then 710°C (1310°F) for 20 hours, air cool. This is used for fasteners and high-strength parts. #### **6. Product Applications** Alloy X-750 is a widely used alloy across several demanding industries: * **Aerospace:** Gas turbine engine blades, disks, seals, rotors, and fasteners. * **Nuclear Power:** Bolting, springs, and core components in pressurized water reactors. * **Springs & Fasteners:** High-temperature springs, bolts, and nuts. * **Tooling:** Hot-work tooling and die inserts. * **Chemical Processing:** Heat exchangers and other high-strength, corrosion-resistant components. #### **7. International and Industry Standards** Alloy X-750 is covered by numerous international and proprietary specifications. * **UNS:** **N07750** * **AMS (Aerospace Material Specification):** * **AMS 5667:** Bars, Forgings, and Rings (Age-Hardened) * **AMS 5672:** Corrosion and Heat-Resistant Wire (Age-Hardened) * **AMS 5542:** Sheet, Strip, and Plate * **ASTM:** **ASTM B637** (Standard Specification for Precipitation-Hardening Nickel Alloy Bars, Forgings, and Forging Stock for High-Temperature Service) * **ASME:** SAE-AMS-5667 (Approved for use in ASME Boiler and Pressure Vessel Code) --- **Disclaimer:** The information provided herein is for reference purposes only. Properties can vary based on product form, size, and specific heat treatment. For design and procurement, the official, latest issue of the relevant material specification and the manufacturer's technical data must be consulted. "Altemp" is a trademark associated with high-temperature alloys.

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 3371 gallon liquid totes Special package is available on request.