Which type of non-destructive testing is most suitable for steel castings

What type of non-destructive testing is suitable for steel castings?

The non-destructive testing methods widely used in casting production include four types: magnetic particle testing, ultrasonic testing, radiographic testing, and penetration testing.

Non destructive testing refers to the detection of castings or non-destructive surface or internal defects. The four widely used methods in foundry production include magnetic particle testing, ultrasonic testing, radiographic testing, and penetration testing.

1. Magnetic particle testing

Mainly used for casting steel and other ferromagnetic materials that will be used in high currents or magnetic fields. Surface defects such as cracks and other substances are not easy to pass through, and defects can only bypass and leak on nearby surfaces, forming local magnetism.

2. Ultrasonic testing

Ultrasonic testing refers to the use of ultrasonic vibration to detect defects in materials or workpieces. According to the testing, ultrasonic vibration is different. He may be a continuous wave generated by continuous vibration, or a pulse wave generated by pulse vibration. Its working principle is roughly the same, but the testing method is different. Ultrasonic testing can be divided into three methods: penetration method, resonance and reflection method.

3. Radiographic testing

Use X-ray and Y-ray transparency or perspective methods to test macro defects in finished or semi-finished products and become radiographic testing. X/Y rays can penetrate substances that ordinary light cannot penetrate; It has photochemical effects, ionization effects, and fluorescence phenomena in certain substances in the population. These functions increase with the increase of radiation intensity.

4. Penetration testing

This is a method for checking surface defects. It needs to apply penetrant to the surface of the cleaned workpiece to allow defects to penetrate, and then remove excess penetrant from the surface to visually apply a layer of imaging agent to display defects.