General knowledge of hand-held laser welding machine (I)
Laser scanning has a great influence on the welding effect of laser welding machine after all. The size of the tortuous viewpoint formed by each laser scanning is related to the heat input density AED of laser scanning.
In the temperature gradient forming mechanism, the larger the AED is, the larger the shrinkage plastic deformation formed by the laser irradiation area on the scanning line during the heating process is, the larger the shortening after cooling is, the greater the tortuous viewpoint of the attack.
When P and d are constant, the larger the scanning rate v is, the smaller the cumulative heat input density is, and the smaller the winding angle is, the smaller the included angle of the connection curve between the zigzag angle and the scanning times.
Therefore, controlling the heat input density during the laser welding process is the key factor for controlling and controlling the welding, while the same heat input density can be adjusted by adjusting different process parameters (
Such as adjusting scanning speed, beam spot diameter and laser power)To get.
The hand-held laser welding machine selects the same power, the same beam diameter and different scanning times to discuss the cumulative heat input density: the heat affected zone on the tracing line (HAZ)The connection between scales. Use L to characterize the width of HAZ.
The contact curve of L, D and cumulative heat input density.
When the cumulative heat input density is very small, the arrangement of the heated area of titanium alloy has no significant change.
There is a threshold value for attack HAZ, which is lower than this value. No attack HAZ, that is, no attack arrangement changes. Beyond this threshold, the attack of HAZ.
In laser welding, with the addition of cumulative heat transmission density, L and D become second-line secondary curves, and tend to be stable after reaching a certain value.
It can be seen that with the addition of AED, HAZ shape and giant fine attack changed significantly. HAZ tracing of different AED values.