There are few mechanical parts that have to withstand loads as great as those imposed on turbines in hydroelectric power plants. Water gushes out under high pressure from specially designed nozzles before hitting the individual blades at a high speed. The blade that is hit first drives the wheel a short distance, but is then idle again for a revolution, resulting in high alternating forces in the root area of the blade.
To prevent fatigue fractures in the root area, turbine makers anneal the weld between the turbine wheel and blade. This relatively gentle, heating process improves the durability of the part significantly. However, the heating must be reproducible and carried out with high precision to ensure turbine quality requirements are met.
Medium frequency (MF) induction heating generators from eldec LLC control the heat easily via a practical LED display:
- Red means the temperature is too high.
- Blue means it is too low.
- Green is just right.
The user also benefits from the speed of the annealing process, which is completed in seconds. Since heat is generated directly in the workpiece, using an alternating electromagnetic field, the process can be carried out very precisely, quickly, and with high-energy conversion efficiency.
Annealing water turbine blade welds is just one example of how the process can be used to stress-relieve parts. Learn more about how eldec can help you prevent part fatigue fractures in your operation.