Detection of weld pool width using infrared imaging during high-power fiber laser welding of type 304 austenitic stainless steel

Abstract

Thermal radiation of a weld pool contains plenty of welding quality information in a high-power fiber laser welding process, in which the weld pool width can reflect the welding stability. Thus, extracting the weld pool width characters of high-power fiber laser welding based on infrared imaging is an important method for monitoring the welding status. In this paper, the type 304 austenitic stainless steel is welded by a 10-kW high-power fiber laser continuously. A high-speed infrared video camera is employed to capture the infrared images of weld pools and their surroundings in the laser welding process. The infrared image characteristics of a weld pool are analyzed, and the improved homomorphic filtering algorithm based on Fourier transform is used to extract weld pool width which depends on the characteristic variation of weld pool images. And the comparison between improved homomorphic filtering algorithm and traditional homomorphic filtering algorithm is also discussed. Welding experimental results show that the proposed improved homomorphic filtering algorithm can extract the weld pool width and reflect the status of high-power fiber laser welding process accurately.