Inventory of methods to detect internal cracks in aluminum alloy die castings!

1. Ultrasonic flaw detection

Ultrasonic inspection and ultrasonic thickness measurement of various metal pipes, plates, castings, forgings and welds. When ultrasonic waves encounter defects such as cracks, voids, segregation, etc. during the propagation process, the acoustic parameters such as the speed, amplitude, and frequency of the ultrasonic waves will change. According to the measurement of these changes by the instrument, the existence of the defect can be judged and its specific location can be determined

Ultrasonic pulses (usually 1.5MHz) shoot the object under inspection from the probe. If there is a defect inside, there is an interface between the defect and the material, the ultrasonic waves shot by some people will be reflected or refracted at the defect, and some unidirectional ultrasonic energy will be reflected, and the energy passing through this interface will be reduced accordingly. At this time, the reflected wave at the defect can be received in the reflection direction; the ultrasonic energy received in the propagation direction will be lower than the normal value, both of which can prove the existence of the defect. In the process of flaw detection, the performance of the probe to receive the pulse signal can also check the location and size of the defect. The former is called reflection method, and the latter is called penetration method.

2. Magnetic particle inspection

It is suitable for non-destructive testing of ferromagnetic materials such as cast, forged and other processed parts.

3. Ultraviolet light

Low price, high reliability, simple operation, check the leakage of various pipelines, whether the coating is uniform, detection of impurities or stains, semiconductor and biological fields, medical and stage artistic effects.

4. Radiographic inspection

Radiographic flaw detection can be divided into X-ray, γ-ray and high-energy ray flaw detection.