Water jet stagnation pressure
Waterjet stagnation pressure is the pressure generated when the high-pressure waterjet impacts the material surface and initiates plastic deformation. It increases with the square of the exit velocity.
Physical-Chemical Mechanism of Action
The water jet stagnation pressure is created by the impact energy of the water on the material surface. The higher the water jet velocity, the stronger the impact and the resulting pressure. This pressure can plastically deform the surface.
Metallurgical Relevance & Welding Risks
Excessive stagnation pressure can damage the material surface, leading to corrosion or material loss. Furthermore, the pressure can affect the crystal structure and change the mechanical properties of the material. This can reduce strength and toughness.
Shop Practice & Action Guidelines
To set the water jet stagnation pressure optimally, control the water exit velocity. A typical exit velocity is about 300 m/s. If the velocity is too high (above 400 m/s), the stagnation pressure can be so high that it damages the material surface. If the velocity is too low (below 200 m/s), the pressure is low and deformation is limited.