Yoke Magnet
A yoke magnet is a hand-held electromagnet or permanent magnet that introduces a defined magnetic field into a confined area of a ferromagnetic component. It is commonly used in metallurgy and mechanical engineering to magnetize metals or control the hardness of workpieces.
Physico-Chemical Mechanism of Action
A yoke magnet generates a homogeneous magnetic field in a defined area. This happens through the flow of current through an electromagnet or the magnetic arrangement of a permanent magnet. The magnetic field acts on ferromagnetic materials and magnetizes them or influences their magnetic properties.
Metallurgical Relevance & Welding Risks
In the workshop, a yoke magnet is often used to control the hardness of steels. By magnetizing and then cooling, the material's hardness can be increased. However, an incorrectly applied yoke magnet can lead to overhardening, which impairs the toughness and mechanical strength of the workpieces. Additionally, a missing or misadjusted yoke magnet can cause metals to not be fully magnetized, leading to problems in certain applications.
Workshop Practice & Instructions
To use a yoke magnet correctly, the following steps must be observed:
1. Magnetization: Ensure the magnetic field generator is correctly switched on and the desired magnetic field is achieved.
2. Application: Insert the workpieces into the area of the magnetic field and hold them there for the specified time.
3. Cooling: After magnetization, the workpiece must be cooled to stabilize the desired hardness. This can be done by natural cooling or controlled cooling processes.
4. Monitoring: Continuously monitor the temperature and magnetic field to ensure no overhardening occurs.