Laser Keyhole Welding
Laser deep welding is a joining process with high power density that forms a capillary-like opening in the melt via metal vapor pressure. It enables high welding speeds and large depth-to-width ratios.
Physical-Chemical Operating Principle
Laser deep-penetration welding uses the high power density of a laser to create a small opening in the weld pool. The laser beam generates a strong metal vapor pressure that penetrates the workpiece while simultaneously creating a capillary-like opening.
Metallurgical Relevance & Welding Risks
The high power density of the laser leads to rapid cooling and significant stress buildup in the material. This can cause cracks or distortion if the welding parameters are not set correctly. Additionally, the laser can alter the surface material, affecting mechanical properties.
Workshop Practice & Instructions
To work successfully with laser deep-penetration welding, the following parameters must be observed:
• Laser power: 100 to 300 W for thin steels, 500 to 1000 W for thick steels.
• Travel speed: 2 to 4 mm/s for thin steels, 1 to 2 mm/s for thick steels.
• Distance from laser head to surface: 3 to 5 mm for thin steels, 8 to 10 mm for thick steels.
• Shielding gas (e.g., argon): Flow rate from 2 to 4 liters per minute.
These settings must be adjusted according to material and welding requirements.