Yoke magnet
A portable electromagnet used to generate a magnetic field in the workpiece during magnetic particle testing. It is used for quick detection of surface flaws in welds on site.
Physico-Chemical Mechanism of Action
A hand magnet generates a magnetic field by passing electric current through a coil. This magnetizes the surrounding metal part, causing fine magnetic particles or powder to accumulate at surface defects like cracks or flaws.
Metallurgical Relevance & Welding Risks
Magnetic particle testing with a hand magnet is particularly useful for quickly checking surface defects in welds. An inaccurate result can lead to missed or incorrect defect detection, posing safety and service life risks for the component.
Workshop Practice & Action Guidelines
To use a hand magnet effectively, follow these steps:
1. Prepare the metal part by cleaning it and removing any surface contamination.
2. Connect the hand magnet to a suitable power source and activate it.
3. Spray or apply fine magnetic particles or powder to the magnetized surface.
4. Slowly move the part over a dark background to observe powder accumulation at defects.
5. Document all visible defects and perform necessary repairs.