Keyhole effect
The keyhole effect occurs in high-energy processes like laser or electron beam welding. Here a vapor-filled capillary channel is formed through the material, producing very narrow and deep welds.
Physical-Chemical Mechanism of Action
In high-energy beam welding processes, the energy is concentrated so intensely that it brings the material into a state of high pressure and temperature. This causes rapid melting of the material and the formation of a vapor-filled capillary channel.
Metallurgical Relevance & Risks in Welding
The keyhole effect allows for very fine and deep welds, which is crucial for specialized applications such as electronics or medical technology. However, excessive pressure or temperature can cause overpressure in the material, leading to cracks or distortion. Additionally, the material around the weld may coarsen, impairing its mechanical properties.
Workshop Practice & Instructions
To make the most of the keyhole effect, the energy settings of the laser or electron beam must be precisely adjusted. This includes selecting the correct wavelength, beam voltage, and welding speed. It's also important that the material is dry before welding to ensure optimal pressure and a homogeneous melting process.