Principles of turbine blade selection

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6.2 Coating material
In addition to being used as a solid blade, cobalt alloy can also be used as a coating on the surface of turbine blades. Applying a layer of cobalt alloy to the blade surface will improve its wear resistance and corrosion resistance, and extend its service life. This coating technology has been successfully applied in many power plants.

STP 6 Chemical composition
C: 0.9-1.4%, Mn: ≤1.0%, Si: ≤1.5%, Cr: 27.0-31.0%, Ni: ≤3.0%, Mo: ≤1.5%, W: 3.5-5.5%, Co: Bal.

Density: ≥8.35g/cm3

Hardness: 38-44HRC

STP 6B Chemical composition
C: 0.9-1.4%, Mn: ≤2.0%, Si: ≤2.0%, Cr: 28.0-32.0%, Ni: ≤3.0%, Mo: ≤1.5%, W: 3.5-5.5%, Co: Bal.

Density: ≥8.38g/cm3

Hardness: 36-40HRC

7.1 Selection of material
According to the characteristics of the working environment of the blades, select materials with excellent corrosion resistance and wear resistance. For example, induction brazing of cobalt alloys on hungary number data SUS410Cb blades can greatly improve the wear resistance and erosion resistance of the blades. At the same time, factors such as material strength, toughness, thermal stability and processability should be considered.

7.2 Structural design
Optimize the shape and size of the blades to reduce stress concentration and vibration. The aerodynamic performance and fatigue strength of the blades can be improved by proper streamlined design and thickness distribution. In addition, factors such as the connection method and the way the blades are attached to the wheel disc must be considered.