Study On Metal Welds Of Infrared Non-destructive Testing Technology

With the development of metallurgy, aerospace and machinery industry, welding position status of welding in the production is getting more and more higher. In the process of Welding, various welding defects in the internal of the Workpiece must occur due to the impact of construction and many other factors.These defects must affect the performance of the Workpiece. A more accurate methods to inspect and assess defects is needed. The traditional means of detection is not only slow, and may cause damage to the workpiece.As a new means of detection, infrared nondestructive testing technology is accurate, intuitive and fast. Based on the basic principles of infrared radiation law, It transfers radiation energy into visible light image by means of infrared imaging technology, and determines the existence of internal defects through the analysis of infrared thermography.Infrared nondestructive testing in the detection of defects in metal and nonmetal has a broad market and application value.Compared to other countries, Our country in the infrared technology started later,the technology has not been more widely used. Because the technology is intuitive, portable and high precision, studying and using this technology has a great practical significance.In this paper,we take metal welds as an example.Considering the characteristics of the infrared image, the paper takes measures to procoss the infrared images.The fuzzy theory is applied to extract a more sharp edges, providing the basic conditions for subsequent detectiones.Based on heat transfer theory,the paper use the finite element numerical analysis software ansys simulate a metal plate with different sizes, different locations.At last ,finite element analysis is carried out to provide theoretical foundation for further applications. Work in the following aspects.1.Introduce the theory of infrared nondestructive testing in detail and the principle.2.Analyze the characters of infrared thermal images based on the principle of thermal imaging. in order to get a clear edge,fuzzy mathematical theory is applied to the field of infrared image edge detection in this paper,so that the edges meeting the purpose of qualitative detection of defects are geted.3.Derive one-dimensional heat transfer model combining the heat conduction theory. And introduces the finite element theory, the theory is applied to transient and steady-state thermal analysis.At the last finite element analysis software ansys is carryed out to establishe a model for the transient analysis, the surface temperature distribution are geted. post-processor general-purpose POST1 and POST26 are used analyse the result.