Influence of full penetration welding on the multispectral signal of the process radiation during laser beam welding of austenitic stainless steel

Abstract

A 100% visual inspection of the welds carried out is not always possible for economic reasons. Different methods of process monitoring are therefore used for non-destructive testing of process and weld seam quality. In the following, the recorded multispectral signals of the reflective process radiation are evaluated using descriptive statistics and characteristics of a full penetration weld during laser beam welding of austenitic stainless steel are worked out. The aim is to detect and localize unintentional full penetration welding at an early stage and thus avoid rejects. For this purpose, adapted sample geometries with varying material thicknesses are prepared for the test series. As a result, the need to vary the welding process parameters to achieve the different welding states (full and partial penetration weld) is avoided. By evaluating the measured values of the wavelength-selective signals, a significant influence on the signal intensity and the signal frequency could be confirmed.