With the great development of science and technology, especially computer technology, digitalization and image recognition technology, artificial neural network technology and mechatronics technology, nondestructive testing technology has made rapid progress.
in radiographic inspection, radiographic imaging and automatic defect identification technology, radiographic computer-aided imaging technology (CR), radiographic real-time imaging technology (DR) and radiographic tomography technology (CT) have been widely used. Fast X-ray real-time imaging system for container inspection, and various industrial CT devices with X-ray, γ-ray and linear accelerator as radiation sources have been widely used in various industrial fields. Micro-focus X-ray CT can detect micro-defects.
in ultrasonic testing, various digital ultrasonic flaw detectors are widely used. TOFD ultrasonic testing system, ultrasonic imaging testing system, magnetostrictive ultrasonic guided wave testing system and phased array ultrasonic testing system have been widely used. In the research of detection method and application technology, a great deal of research results have been achieved mainly in automatic ultrasonic detection technology, ultrasonic imaging detection technology, artificial intelligence and robot detection technology, TOFD ultrasonic detection technology, ultrasonic guided wave detection technology, non-contact ultrasonic technology, phased array ultrasonic detection technology and laser ultrasonic detection technology. Multi-channel ultrasonic flaw detector used in automatic inspection line of pipe, bar and welded pipe has 5 channels and the highest sampling rate is 24MHz. Ultrasonic guided wave detection system and magnetostrictive guided wave detection method have been used for long-distance detection of corrosion defects in industrial pipelines and buried pipelines with insulation layer. In electromagnetic testing, all conventional eddy current testing instruments are digitized, and array probes and multi-channel instruments have been developed, realizing the application of advanced electronic and information technologies such as data conversion and analysis. Far-field eddy current, multi-frequency eddy current, pulsed eddy current and magneto-optical/eddy current imaging detection technologies have been developed and applied. Pulsed eddy current detection technology is used for corrosion detection of steel pressure vessels and pipelines with insulation layer, which can penetrate the insulation layer with a maximum thickness of 15 mm.
magnetic flux leakage detection technology has been widely used in corrosion detection of large atmospheric storage tank bottom plate, on-line detection of pipeline manufacturing process, steel wire rope detection, oil drill pipe detection and industrial pipeline corrosion detection without insulation layer. Magnetic memory testing has been widely used in power plant boilers, pressure vessels, pressure pipes, steam turbines, wind turbines and bridges. Backhausen noise technology is more widely used in residual stress detection.
in acoustic emission detection, various advanced multi-channel acoustic emission instruments are constantly emerging. In the analysis and processing of acoustic emission signals, including conventional parameter analysis, time difference location, correlation graph analysis, frequency spectrum analysis, wavelet analysis, pattern recognition, artificial neural network pattern recognition, fuzzy analysis and grey correlation analysis, etc. have been applied. In China, there are more than 5 testing institutions engaged in acoustic emission testing of pressure vessels all the year round. It has also made great progress in microwave detection and infrared detection. Microwave detection is widely used in the detection of humidity, temperature, density and curing degree, and also plays an important role in the detection of bonded structures, composite materials and rocket propellants.
infrared detection has been widely used in electric power industry, petrochemical industry, building construction and other fields. Applied research has also been carried out in the fields of metal mechanics samples, fracture mechanics and stress analysis, fault analysis of printed circuit boards and ceramic industry. Infrared thermal imaging detection of pressure vessels has been formally incorporated into the safety supervision laws and regulations system of special equipment in China. In-service inspection is an important method for safety supervision of in-service equipment and structures. It has been widely used in special equipment such as pressure vessels, oil and gas pipelines, aviation systems, railway systems, civil engineering and steel structures, nuclear power plants and other fields, and has made remarkable achievements.
the theory and regulations of reliability evaluation of existing structures have been unanimously recognized internationally. Non-destructive testing technology has played an important role in the reliability evaluation of in-use equipment and structures.
nondestructive testing technology is also playing an irreplaceable role in coping with climate change, developing low-carbon economy, circular economy and green remanufacturing industry.
At present, China has 17, NDT personnel and more than 2, NDT institutions (excluding internal inspection rooms), which play an important role in national economic construction and personal and equipment safety monitoring.