Study Of The Micro-magnetic Detection Method For T-fillet Weld

In engineering the manufacturing process, the connection of most components should be adopted such a fillet weld form, and T-type fillet weld is the most typical type. In the process of utilizing workpieces, the fillet weld is a relatively weak part. However, it will make cracks, porosity, incomplete penetration or inclusions and other defects in the welding process, due to improper operation or negative environmental factors. Although there are many methods to detect fillet weld’s defect, the result will be subjected to environmental restrictions or detection efficiency. Therefore, this paper presents a new non-destructive testing technique, micro-magnetic detection technology, which only uses a natural geomagnetic field in order to detect the defects in the T-fillet weld.In this experiment, the objects of the research are two different types of T-fillet weld, one only contains artificial defects and another only contains natural defects. First of all, micro-magnetic detection systems tests the specimens only containing artificial defects. Then, the data collected by test equipment are processed based on the field gradient theory and the theory of probability theory. In this way, position of the defects and the defect signals can be detected. The study shows that using the micro-magnetic detection system to detect T-fillet specimens is feasible; using an array of the micro magnetic detection system detects the T-fillet weld which has rougher surface. The defect signals can be determined by the resulting after the resulting data processed by differential encoding from the last step. The test results show that the array micro magnetic detection system can better detect the T-fillet weld defects. Third, utilizing Matlab software can image the defects through the collected defect signals, which achieves the defect signal visualization and makes the defect location and size more intuitive. Finally, using radiation detection method tests T-fillet weld which only contains natural detection. The results demonstrate that the data from the micro magnetic detection system is the same as the micro-magnetic radiation test. In conclusion, micro-magnetic detection method to test T-fillet weld is feasible and reliable. Research on this topic, it provides new ideas and methods for testing T-fillet weld in non-destructive testing field.