To evaluate the quality of a weld produced by a stud welding process, the time characteristic of the resistance R (t) between the stud and the workpiece is determined. If the resistance or the increase in resistance or the rate of increase of the resistance exceeds a predetermined value during the arc period, this is an indication of arc blow effects, of spattering, and of the arc burning outside the bonding area--effects which impair the quality of the weld. Upon detection of a predetermined resistance increase, the weld process is terminated by turning off the weld current or by immediately immersing the stud into the melt of the workpiece. Alternatively, the characteristic of the resistance over time detected in a first welding process can be used to set the parameters for subsequent welding processes.