A turbine casing is the outer shell structure of a turbine (such as a steam, gas, or hydraulic turbine).
It serves to contain high-temperature and high-pressure fluids inside the turbine and to support and align the rotor assembly.
2. Configuration
Turbine casings are generally composed of:
Upper Casing
→ Can be detached for inspection and assembly.
Lower Casing
→ Fixed to the foundation and supports the rotor and bearings.
This split design is called a Horizontal Split Casing, commonly used for large-scale turbines such as power generation units.
3. Materials
The casing material is selected according to the operating temperature and pressure:
Carbon Steel – for general pressure service
Low Alloy Steel – for medium temperature and pressure
Cr-Mo Steel (Chromium-Molybdenum Alloy Steel) – for high-temperature and high-pressure service
Nickel Alloy / Stainless Steel – for very high-temperature or corrosive environments