Alloy 188,Haynes 188,UNS R30188,E FORU

### **Alloy 188 / Haynes® 188 / UNS R30188** **Cobalt-Chromium-Nickel-Tungsten Superalloy for Enhanced Oxidation Resistance

** --- #### **1. Overview** **Alloy 188**, commercially known as **Haynes® 188**, is a cobalt-chromium-nickel-tungsten superalloy that exhibits an exceptional combination of high-temperature strength, outstanding oxidation resistance (up to 1150°C/2100°F), and excellent fabricability. This solid-solution strengthened alloy offers superior resistance to thermal fatigue and maintains its properties over long periods of exposure at elevated temperatures. The addition of lanthanum significantly improves the alloy's oxidation resistance by promoting a tightly adherent protective scale. 

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

** The typical chemical composition of Haynes 188 is outlined below. The balance is Cobalt (Co). 

| Element | Content (%) | Key Function | 

| :--- | :--- | :--- | 

| **Cobalt (Co)** | Balance | Provides the fundamental matrix with excellent high-temperature structural stability. | 

| **Chromium (Cr)** | 20.0 - 24.0 | Imparts exceptional oxidation and hot corrosion resistance through Cr₂O₃ scale formation. | 

| **Tungsten (W)** | 13.0 - 15.0 | Primary solid-solution strengthener; enhances high-temperature strength and creep resistance. | 

| **Nickel (Ni)** | 20.0 - 24.0 | Stabilizes the austenitic structure and improves metallurgical stability. | 

| **Iron (Fe)** | 3.0 max | Controlled impurity. | 

| **Lanthanum (La)** | 0.03 - 0.12 | Dramatically improves oxidation resistance by enhancing scale adhesion and reducing spallation. | 

| **Manganese (Mn)** | 1.25 max | Aids in sulfur control and hot workability. | 

| **Silicon (Si)** | 0.20 - 0.50 | Enhances oxidation resistance. | 

| **Carbon (C)** | 0.05 - 0.15 | Forms carbides for secondary strengthening. | 

| **Boron (B)** | 0.015 max | Enhances creep strength. | 

| **Phosphorus (P)** | 0.02 max | - | 

| **Sulfur (S)** | 0.015 max | - | 

 --- #### **3. Physical Properties** 

| Property | Value / Condition | 

| :--- | :--- | 

| **Density** | 9.13 g/cm³ (0.330 lb/in³) | 

| **Melting Range** | ~ 1330 - 1410 °C (2425 - 2570 °F) | 

| **Mean Coefficient of Thermal Expansion** | 20 - 540°C (68 - 1000°F): **14.2 x 10⁻⁶/°C** (7.9 x 10⁻⁶/°F) | 

| **Thermal Conductivity** | 10.0 W/m·K (69 Btu·in/hr·ft²·°F) at 21°C (70°F) | 

| **Specific Heat** | 421 J/kg·K (0.101 Btu/lb·°F) at 21°C (70°F) | 

| **Electrical Resistivity** | 0.95 μΩ·m at 21°C (70°F) | 

| **Modulus of Elasticity (Young's Modulus)** | 248 GPa (36.0 x 10⁶ psi) at 21°C (70°F) | 

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

 --- #### **4. Mechanical Properties

 (Typical for Annealed Condition)** 

| Property | At Room Temperature | At 815°C (1500°F) | At 980°C (1800°F) | 

| :--- | :--- | :--- | :--- | 

| **Tensile Strength** | 965 MPa (140 ksi) | 310 MPa (45 ksi) | 165 MPa (24 ksi) | 

| **Yield Strength (0.2% Offset)** | 485 MPa (70 ksi) | 220 MPa (32 ksi) | 125 MPa (18 ksi) | 

| **Elongation (in 50 mm / 2 in)** | 50% | 60% | 75% | 

| **Hardness (Rockwell B)** | 96 HRB | - | - | 

 --- #### **5. International Standards

** Haynes 188 is covered by the following international specifications: 

 *   **ASTM:**    

*   **B435:** UNS R30188 Plate, Sheet, and Strip    

*   **B572:** UNS R30188 Rod/Bar 

*   **AMS:**    

*   **AMS 5803:** Welding Wire    

*   **AMS 5772:** Sheet, Strip, and Plate 

*   **UNS:** R30188 

*   **ISO:**    

*   **ISO 5832-7:** Wrought cobalt-chromium-nickel-molybdenum-iron alloy 

 --- #### **6. Product Applications

** Haynes 188 is utilized in extreme environment applications across various industries: 

 *   **Aerospace:**    

*   Combustion chambers and liners    

*   Afterburner components    

*   Turbine blades and vanes    

*   Exhaust system components 

*   **Industrial Gas Turbines:

**    *   Transition ducts    

*   Combustion cans 

*   **Heat Treating:

**    *   Furnace fixtures and radiant tubes 

*   **Power Generation:*

*    *   Gas turbine components 

*   **Medical:

**    *   Dental prosthetics    

*   Surgical implants 

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

** *   **Exceptional oxidation resistance

** up to 1150°C (2100°F) 

*   **Excellent high-temperature strength

** and creep resistance 

*   **Good thermal fatigue resistance

** *   **Superior fabricability** and weldability 

*   **Excellent structural stability** during long-term exposure 

*   **Outstanding resistance to sulfidation**

 --- **Disclaimer:

** *Haynes® 188 is a registered trademark of Haynes International, Inc. 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 188,Haynes 188,UNS R30188

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 1668 gallon liquid totes Special package is available on request.