Method of Detecting Internal Cracks of Steel Products using Laser-Ultrasonic

摘要

PURPOSE: A method for measuring faulty of metal by using laser inducing ultrasonic waves is provided to improve quality of a product by reducing faulty through exactly detecting the faulty of the metal and to reduce a producing cost. CONSTITUTION: A laser is injected to a test sample of metal and then is reflected to a mirror slantingly mounted in the middle of the test sample. Then the test sample is crashed to the laser to generate ablation effect melting the metal by crashing the laser. Then, ultrasonic waves are generated in the test sample by repulsive force of the ablation effect. An ultrasonic transducer is installed on a rear portion of the test sample without contacting to the test sample with a specific interval. Am amplifier amplifies the ultrasonic detected from the ultrasonic transducer to exactly analyze the ultrasonic wave. The amplified ultrasonic is transferred to an oscilloscope to output corrugation. A low laser generates the ultrasonic by thermo elastic effect. A high laser generates strong ultrasonic on a surface of material by the ablation effect.