Alloy PK33,Nimonic PK33,,E FORU

### **Alloy PK33 / Nimonic® PK33** **High-Strength Nickel-Based Superalloy for Advanced Turbine Applications

** #### **1. Overview

** **Alloy PK33**, commercially known as **Nimonic® PK33**, is a precipitation-hardenable nickel-chromium-cobalt superalloy designed for high-stress applications at elevated temperatures. This advanced superalloy offers an optimal combination of high-temperature strength, excellent creep resistance, and good oxidation resistance, making it suitable for critical rotating components in gas turbine engines. Nimonic PK33 maintains its mechanical properties at temperatures up to 850°C (1562°F) and is particularly valued for its balanced performance in demanding aerospace applications. 

 #### **2. Chemical Composition (Weight %)

** The typical chemical composition of Nimonic PK33 is outlined below. The balance is Nickel (Ni). 

| Element | Content (%) | Key Function | 

| :--- | :--- | :--- | 

| **Nickel (Ni)** | Balance | Forms the austenitic matrix and provides fundamental high-temperature capability. | 

| **Chromium (Cr)** | 18.0 - 21.0 | Provides oxidation and hot corrosion resistance. | 

| **Cobalt (Co)** | 16.0 - 20.0 | Enhances solid-solution strengthening and raises γ' solvus temperature. | 

| **Molybdenum (Mo)** | 3.5 - 4.5 | Provides solid-solution strengthening and enhances creep resistance. | 

| **Aluminum (Al)** | 1.2 - 1.8 | Primary precipitation hardening element forming γ' phase (Ni₃Al). | 

| **Titanium (Ti)** | 2.8 - 3.3 | Co-precipitates with aluminum to form γ' phase (Ni₃(Al,Ti)). | 

| **Iron (Fe)** | 1.5 max | Controlled impurity; kept low to maintain high-temperature properties. | 

| **Manganese (Mn)** | 0.50 max | Improves hot workability. | | **Silicon (Si)** | 0.50 max | Enhances oxidation resistance. | 

| **Carbon (C)** | 0.10 - 0.17 | Forms carbides for grain boundary strengthening. | 

| **Boron (B)** | 0.003 - 0.008 | Enhances creep strength and grain boundary cohesion. | 

| **Zirconium (Zr)** | 0.02 - 0.08 | Improves creep-rupture properties. | 

| **Copper (Cu)** | 0.20 max | Controlled impurity. | 

| **Sulfur (S)** | 0.010 max | Impurity, kept very low to prevent hot shortness. |

 #### **3. Physical Properties** 

| Property | Value / Condition | 

| :--- | :--- | 

| **Density** | 8.15 g/cm³ (0.294 lb/in³) | 

| **Melting Range** | ~ 1345 - 1395 °C (2453 - 2543 °F) | 

| **Mean Coefficient of Thermal Expansion** | 20 - 500°C (68 - 932°F): **14.0 x 10⁻⁶/°C** (7.8 x 10⁻⁶/°F)
20 - 800°C (68 - 1472°F): **15.1 x 10⁻⁶/°C** (8.4 x 10⁻⁶/°F) | 

| **Thermal Conductivity** | 16.2 W/m·K (112 Btu·in/hr·ft²·°F) at 20°C (68°F)
24.5 W/m·K (170 Btu·in/hr·ft²·°F) at 800°C (1472°F) | 

| **Specific Heat** | 455 J/kg·K (0.109 Btu/lb·°F) at 20°C (68°F) | 

| **Electrical Resistivity** | 1.25 μΩ·m at 20°C (68°F) | 

| **Modulus of Elasticity (Young's Modulus)** | 222 GPa (32.2 x 10⁶ psi) at 20°C (68°F) | 

| **Magnetic Permeability** | Essentially non-magnetic. | 

 #### **4. Mechanical Properties 

(Typical for Aged Condition)** 

 | Property | At Room Temperature | At 750°C (1382°F) | At 850°C (1562°F) | 

| :--- | :--- | :--- | :--- | 

| **Tensile Strength** | 1100 - 1300 MPa (160 - 189 ksi) | ~650 MPa (94 ksi) | ~450 MPa (65 ksi) | 

| **Yield Strength (0.2% Offset)** | 750 - 900 MPa (109 - 131 ksi) | ~550 MPa (80 ksi) | ~380 MPa (55 ksi) | 

| **Elongation (in 50 mm / 2 in)** | 12% - 20% | 10% - 18% | 12% - 22% | 

| **Reduction of Area** | 15% - 25% | 12% - 20% | 15% - 25% | 

| **Hardness (Rockwell C)** | 30 - 38 HRC | - | - |

 #### **5. International Standards

** Nimonic PK33 is covered by several international and industry-specific standards: 

* **ASTM:**  * **B 637:** Standard Specification for Precipitation-Hardening Nickel Alloy Bars, Forgings, and Forging Stock for High-Temperature Service 

* **AMS:**  * **AMS 5764:** Bar, Forgings, and Rings  * **AMS 5801:** Welding Electrode 

* **BS / EN:**  * **BS HR 510:** Aerospace series  

* **EN 10095:** Heat resisting steels and nickel alloys 

* **DIN:** 2.4971 (Material Number) 

* **ISO:** ISO 9723, ISO 9724 

* **AECMA:** PR EN 2957 

 #### **6. Product Applications

** Nimonic PK33 is used in critical high-temperature applications requiring reliable performance: 

 * **Aerospace Gas Turbines:

**  * Turbine blades and vanes  

* Discs and rotors  

* Shaft components  

* Combustion chamber parts 

* **Industrial Gas Turbines:

**  * Turbine blades  

* Rotor assemblies  

* High-temperature structural components 

* **Power Generation:

**  * Advanced gas turbine components  

* High-temperature fastening systems 

* **Marine Propulsion:

**  * Gas turbine components for naval vessels  

* High-temperature exhaust systems 

 #### **7. Key Characteristics & Advantages

** * **Excellent High-Temperature Strength:

** Maintains superior mechanical properties at temperatures up to 850°C (1562°F) 

* **Outstanding Creep Resistance:

** Excellent long-term creep performance under high stress conditions 

* **Balanced γ' Precipitation:

** Optimized aluminum and titanium content provides effective precipitation hardening 

* **Good Oxidation Resistance:

** Suitable for long-term service in high-temperature environments 

* **Thermal Stability:** Maintains microstructural integrity during extended high-temperature exposure 

* **Good Fatigue Resistance:

** Withstands cyclic loading conditions at elevated temperatures 

* **Proven Reliability:

** Established service history in demanding aerospace applications 

 --- **Disclaimer:

** *Nimonic® is a registered trademark of Rolls-Royce plc. The values provided are typical and for informational purposes only. For critical applications, always consult the official material data sheets from the supplier and relevant design codes.*

Packing of Alloy PK33,Nimonic PK33,

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 1665 gallon liquid totes Special package is available on request.