Definition
RT ray flaw detector is a non-destructive testing equipment based on the principle of ray penetration, which is mainly used to detect macroscopic geometric defects inside materials or workpieces, such as porosity, slag inclusion, non-welding, cracks, etc. Its core is to generate penetrating radiation through the ray source, and use the attenuation difference of the inspected object to form an image on the recording medium to evaluate the integrity of the internal structure.
Principle
The working principle of RT ray flaw detectors is based on the interaction of rays with matter. When rays pass through the object being inspected, they will be attenuated to varying degrees due to the density, thickness and atomic number of the material. The law of decay follows the Bill-Lambert law, which is expressed as:
I = I0 e-μt
where I is the intensity of the ray after penetration, I0is the initial ray intensity, μ is the linear attenuation coefficient of the material, and t is the material thickness. The attenuated rays are recorded by the detector or film to form a chiaroscuro image, and the defect area shows abnormal contrast due to changes in thickness or density, enabling defect identification.
Measurement method
Common measurement methods mainly include film method and digital imaging method. The film method uses ray-sensitive film as the recording medium to obtain permanent images through exposure and darkroom processing. The digital imaging method uses a flat panel detector or image intensifier to convert into digital signals in real time, and the image is processed and analyzed through software. During operation, it is necessary to reasonably select parameters such as ray energy, focal length, and exposure time according to the material, thickness and shape of the object to be inspected, and follow standards such as ISO 17636 or GB/T 3323 to ensure the reliability and consistency of detection.
Influencing factors
Test results are influenced by a variety of factors. Ray energy determines penetration, too high will reduce contrast, too low may lead to underexposure; Focal length affects geometric unclearness, and a longer focal length can improve image clarity. The material and thickness of the inspected object directly affect the attenuation coefficient, and the exposure parameters need to be adjusted accordingly. In addition, scattered rays can interfere with image quality, which is usually suppressed by filtering or shielding measures. The operator's experience and understanding of the standard also play a significant role in the accuracy of defect interpretation.
Application
RT ray flaw detectors are widely used in several industrial fields. In the welding process, it is used to detect internal defects in the weld; The casting industry is used to evaluate the shrinkage, looseness and other problems of castings; The aerospace sector is used to check the structural integrity of critical components; In the petrochemical industry, it is used for safety assessment of pipelines and containers. It can provide intuitive internal quality information without damaging the inspected object, providing a basis for process improvement and safe operation and maintenance.
Selection
Technical parameters and application requirements should be comprehensively considered when selecting. The type of ray source (such as X-ray machine or γ-ray source) should be selected according to the penetration ability and site conditions; The type of detector (film, digital flatbed, or line array detector) affects imaging speed and resolution. Equipment portability, power consumption, and protection requirements are also important considerations for on-site testing. At the same time, it is necessary to refer to the provisions of relevant industry standards on sensitivity, unclearness and other indicators, and evaluate the reliability, maintenance costs and operation training needs of the equipment to ensure its compatibility with the detection target.