With the rapid development of electronic technology, especially microelectronics technology, computer technology and ultrasonic transducer technology, the ultrasonic phased array and TOFD detection technology that have emerged in recent years have become the development trend of ultrasonic flaw detection.

 

The ultrasonic phased array integrates multiple wafers (such as 32, 64, 128) in one probe. The excitation time of each wafer can be adjusted separately. The transducer wafer array is composed by controlling parameters such as the beam axis and focus. A scan of the full section of the weld is achieved.

 

The TOFD (diffraction time difference method) detection is a method of detecting defects by means of the diffraction energy obtained from the "end angle" and "end point" of the internal structure (mainly referred to as a defect) of the test piece to be inspected. Two broadband narrow pulse probes are used for detection, and the probes are symmetrically arranged with respect to the center line of the weld. The transmitting probe generates an unfocused longitudinal beam that is incident on the workpiece to be inspected at an angle. A part of the beam is received by the receiving probe along the near surface, and a part of the beam is reflected by the bottom surface and received by the receiving probe. The receiving probe determines the position of the defect and its height by receiving the diffraction signal of the defect tip and its time difference.

 

Based on the phased array technology, the A, B, C and S scans of the weld can be realized. By combining with the TOFD test, the three-dimensional imaging information of the weld defects can be obtained, and the typical flaw detection interface. Under normal circumstances, the detection result of this method can replace radiography, and the positioning is more accurate. It has been used in domestic aviation and nuclear industry, and the effect is very good. In the West-East Gas Transmission Project, the ultrasonic phased array detection technology is in the oil pipeline. The detection of wire-bonded weld corn cobs plays an important role, but due to the high cost of equipment, it is still widely used in the detection of steel structures in construction steel structures.

 

In summary, China's construction steel structure of color steel technology has made great progress and development, in the rapid development of physics, chemistry, metallurgy, materials, electronics, computers, automatic control, etc., with new technologies, new materials With the continuous emergence of new equipment and new processes, the new color steel technology for the manufacture and installation of steel structures in China is bound to be able to develop faster and better, such as: new digital intelligent arc welding inverter power supply, laser color steel and cutting , ultra-high pressure electron beam color steel, color steel robot system, 4C control technology for steel structure production, namely computer aided design (CAD), computer aided processing (CAM), computer aided detection (CAT), computer aided evaluation (CAE), etc. The new technology is gradually involved in the field of construction steel structure, and the level of color steel technology of its construction steel structure will have a new situation.