Sound beam divergence
Beam spread is the widening of the ultrasound cone when passing through a medium. It affects lateral resolution and the directionality of the probe.
Physicochemical Mechanism of Action
Sound beam divergence occurs because the ultrasonic wave field spreads wider when passing through a medium (e.g., steel). This happens due to the different density and elasticity of the medium.
Metallurgical Relevance & Welding Risks
Divergence can impair lateral resolution (the ability to detect small defects). An excessively high directivity factor (the ratio of sound speed in the medium to that in air) leads to poorer inspection results and increases the risk of missed flaws or cracks.
Workshop Practice & Operating Instructions
To optimize lateral resolution, choose a probe with a directivity factor of 1.5 to 2.0. Ensure the medium is homogeneous and free of air bubbles or other distortions. For complex parts, using multiple sound directions can be helpful.