Detection of hot cracks in laser welding

A method for determining quality of a weld seam of a workpiece welded by laser beam welding along the weld seam, the method comprising:

• monitoring, with a measuring system during a laser beam welding operation, at least one parameter that correlates to a molten bath oscillation of a molten bath during the laser beam welding operation;
• establishing, from the at least one parameter, a measurement variable for an amplitude of the molten bath oscillation, or a measurement variable for a frequency of the molten bath oscillation, or both a measurement variable for an amplitude of the molten bath oscillation and a measurement variable for a frequency of the molten bath oscillation;
• determining a probability or a frequency, or both a probability and a frequency, of occurrence for an appearance of hot cracks in the weld seam of the workpiece from the measurement variable for the amplitude of the molten bath oscillation, or the measurement variable for the frequency of the molten bath oscillation, or from the measurement variable for the amplitude and for the frequency of the molten bath oscillation;
• and
• determining quality of the weld seam of the workpiece based on the probability or frequency, or based on both the probability and the frequency, of occurrence for the appearance of hot cracks in the weld seam.