Deep penetration welding - SIAD Società Italiana Acetilene e Derivati
Deep Penetration Welding header
Deep Penetration Welding
A laser beam with power density in excess of 106 - 107 W/cm2 is focused on the surface to be welded and vaporises the metal at the point of contact.
This generates a small capillary of ionized metallic vapour (known as “Plasma”) which is capable of almost completely absorbing the power of the Laser, transferring it into the depths of the metal.
The results are:
- a high depth to width ratio of the weld bead (6-8);
- limited heat transfer to the adjacent material;
- high work speed;
- minimal distortion.
Penetration welding is the most widely used technique in industry today. Often, the Plasma which forms is so intense (laser power too high or speed too slow) that it is discharged from the capillary itself, giving way to a reduction in power on the inside of the material (the Plasma shield effect). This can limit penetration (in this case the weld bead appears higher, with a characteristic nail head shape) or, can, in fact, interrupt the welding process. Due to the different lengths of waves emitted, the effect is more pronounced when using CO2 Laser beams as compared with those emitted by a Ned-YAG source.