Effect of Laser Power on Processing Quality of AZ31B Magnesium Alloy

The laser cutting experiment of AZ31B magnesium alloy was carried out by using a high-power laser cutting machine. The influence of laser power on surface roughness and kerf width was studied. The kerf width, surface roughness, kerf taper, slag height and element distribution were measured by ultra-depth-of-field three-dimensional microscope and scanning electron microscope. The changes of the kerf width and the morphology of the cutting surface were observed, the reasons for the changes of the kerf width and roughness were explored, and the variation of kerf taper and slag height with laser power is studied. The results show that the cutting surface has obvious layering, and there are mainly three major areas: top area, scour area and strip area. The areas of the top area and scour area are decreasing, while the stripe area is expanding. The area changes of the three areas affect the roughness of the cutting surface. With the increase in laser power, the kerf width at the straight line and the kerf width at the sharp corner increase, and the kerf width ratio fluctuates up and down around 1.87, which indicates that the linear relationship between them is maintained under the condition that other parameters are constant. The kerf taper increases with the increase in laser power, and the height of hanging slag reaches the peak when the laser power is 900W.