Ultrasonic flaw detectors are core equipment for industrial non-destructive testing (NDT). Based on the principle of ultrasonic reflection, they detect internal defects in materials with non-destructive, high-precision and fast-response performance, making them indispensable tools for quality control of metals, welds and structural components.
Core Testing Principle
The instrument emits high-frequency ultrasonic waves to penetrate the tested material. When the ultrasonic waves encounter internal defects or material interfaces, reflected echoes are generated. By analyzing the waveform, amplitude and time of the echoes, the equipment accurately determines the position, size and depth of defects without damaging the sample.
Application
- Metal components: Detection of internal cracks, porosity, inclusions and looseness in steel products, forgings, castings, pipes and bars.
- Welding quality: Inspection of incomplete penetration, poor fusion, porosity and slag inclusions in welds of pressure vessels, pipelines and steel structures.
- General industry: Routine non-destructive testing in rail transit, shipbuilding, machinery, electric power and petrochemical industries.
Core Advantages
- High testing accuracy: Capable of identifying tiny internal defects and supporting quantitative defect positioning.
- High efficiency: Handheld and portable models enable rapid on-site testing with low operation threshold.
- Safety and environmental protection: No radiation hazard, more suitable for on-site operation compared with radiographic testing.
- Strong adaptability: Compatible with most metal materials and meets testing requirements across multiple industries.
Main Display Modes
- A-Scan: The most commonly used mode, displaying echoes in waveform to intuitively judge the position and size of defects.
- B-Scan: Presenting cross-sectional images of the workpiece to show the longitudinal distribution of defects.
- C-Scan: Generating planar projection images of the workpiece, suitable for automatic batch testing.
Key Points for Selection and Use
- Prioritize angle probes + shear wave mode for weld testing; low-frequency straight probes for thick workpieces.
- Select portable, long-battery-life and anti-interference models for on-site operation; high-precision models with data storage for laboratories.
- Calibrate the probe, sound velocity and zero point before use to ensure reliable test results.
- Couplant (engine oil, glycerin, water) is essential to eliminate air between the probe and the workpiece and ensure ultrasonic transmission.
