High-Frequency Mechanical Impact Treatment
Pneumatic high-frequency hammering is a mechanical peening method with high strike frequency that increases the fatigue strength of welded structures. It reduces notch sensitivity by rounding the transition zone.
Physical-Chemical Mechanism of Action
Pneumatic high-frequency peening uses a compressible fluid (e.g., air) as the driving medium to move a striking hammer at high speed. This hammer impacts the metal at short intervals, creating mechanical stresses and altering the microstructure.
Metallurgical Relevance & Welding Risks
Peening reduces notch sensitivity and improves fatigue strength by rounding the transition zone between welded and unwelded metal. However, improper application can lead to over-peening or excessive stress, causing cracks or deformation.
Shop Practice & Operating Instructions
Use a striking hammer with a frequency of at least 50 Hz. The hammer force should be between 10 and 20 N. Peen the area for 30 seconds, with the hammer moving at a speed of 10 cm/s. Make sure the metal isn't over-peened to avoid distortion or cracks.