Xue Jiaxiang

Research on Image Resolution in Ultrasonic Imaging Inspection of Welding Defect

The resolution problem of welding seam ultrasonic imaging system is studied in this paper, a triple-stage stepwise solutions is proposed, the measured ultrasonic signal is processed by super-resolution algorithm based on wavelet transform, signal processing result shows: the method is feasible to improve image quality of ultrasound imaging equipment and enhances its ability to identify subtle defects in welding seam. Moreover, the algorithms is under further improving and enhancing in ultrasonic image.

Study on the Comparition of Properties between SPMIG and DPMIG Welding of AA6061 Aluminium Alloy

In order to improve the stability of SPMIG welding process, this paper fully utilized the characteristics that sine wave was the low-frequency modulation signal as well as the sine wave function was derivable for any order to make the energy change dE/dt smooth, thus improving the welding stability and welding joint performance. The tests for the SPMIG and DPMIG welding of AA6061 aluminium alloy were carried out, respectively. Then the test results of two kinds of welding methods in instantaneous current waveform, weld appearance, U-I diagram, probability distribution of current and voltage, weld hardness, microscopic structure of welds, and so on were compared, and the superiority of SPMIG was verified.

Key Techniques on Design of Laser High-speed Video System for Recording Metal Transfer in Arc Welding

The metal transfer process of arc welding with consumable electrode is a complicated procedure that combines momentum, heat and mass transfer as well as transportation. Due to the difficulties of observing fast changing process of melted drop transition, a proper high-speed video system with laser in the background was established for recording the process. Structure of the high-speed video system, design of optic system, selection of laser and preferences of camera lens which have influences on the recording results are introduced. The electrical waveforms and images of welding process were collected in synchronous with the system.