Analysis of the entire process of stainless steel testing: core technologies, methods and applicatio
Posted by： Hangao Time：3/6/2025 1:46:23 PM
With the rapid development of industrial technology, stainless steel pipes play a key role in the fields of petrochemicals, nuclear energy, aerospace, etc. due to their corrosion resistance and high strength. However, the tiny defects (such as cracks, pores, uneven wall thickness, etc.) that may exist during their production and use will directly affect safety and service life. Therefore, non-destructive testing technology has become the core means to ensure the quality of stainless steel pipes. In recent years, with the breakthrough of automation and intelligent technology, stainless steel pipe testing equipment has been continuously upgraded, and a multi-technology collaborative testing system has gradually been formed. This article will systematically introduce the current mainstream five types of stainless steel pipe testing equipment from the perspectives of application scenarios, technical principles, advantages, etc., and explore their technological development trends.
1. Eddy current flaw detection equipment
Principle and application
Eddy current testing is based on the principle of electromagnetic induction. Eddy currents are induced on the surface of stainless steel pipes through alternating magnetic fields. When defects are encountered, the eddy current distribution is distorted, which is captured and analyzed by the probe. According to the detection method, it can be divided into two categories:
Through eddy current testing: suitable for high-speed online detection, it can simultaneously identify problems such as surface cracks, weld leaks and internal inclusions, especially suitable for the high-precision requirements of industrial pipes.
Hood-type eddy current testing: focuses on leaking defects in the weld area, similar to infrared detection functions, but with higher sensitivity.
Advantages: non-contact, efficient and fast (such as a case in the literature with a detection speed of 20mm/s), and can adapt to complex environments (such as the radioactive environment of the inner wall of a nuclear container).
2. Ultrasonic non-destructive testing equipment
Technological innovation
Ultrasonic testing uses the reflection characteristics of high-frequency sound waves in materials to accurately locate internal defects (such as delamination and pores) and quantify their sizes. The new generation of equipment has achieved breakthroughs through the following innovations:
Automated integration: linked with the production line to achieve automatic feeding, parameter adjustment and real-time feedback, and the detection efficiency is improved by more than 40%.
Multi-probe collaboration: adopts a rotating head design, combined with straight probes, oblique probes, etc., to cover multi-dimensional detection needs such as longitudinal cracks and transverse weld defects.
Case: A petrochemical company uses ultrasonic automatic flaw detection equipment to successfully identify tiny cracks in batches of pipes, avoiding potential leakage risks.
3. Infrared detection equipment
Functions and limitations
Infrared detection uses thermal imaging technology to capture the temperature field changes on the surface of stainless steel pipes, and is mainly used for rapid screening of weld leaks. Its advantages are simple operation and low cost, but its functions are single and it is only suitable for scenarios with basic quality requirements (such as civil pipes).
Comparison: Compared with hood-type eddy current detection, infrared technology is not sensitive to deep defects and cannot meet the needs of high-precision industrial pipe detection.
4. Fully automatic diameter gauge
Technological breakthrough
The diameter gauge uses parallel light measurement method to monitor the pipe diameter deviation in real time with a high-frequency acquisition capacity of 2000 times per second, with an accuracy of ±0.01mm. Its innovations include:
Anti-interference design: The filter lens is used to fix the wavelength light source to eliminate the interference of ambient light in the workshop.
Intelligent feedback system: Combined with the PID algorithm, the production line parameters are automatically adjusted to reduce the scrap rate to less than 0.5%.
Application value: After a certain enterprise introduced the diameter gauge, it realized the full closed-loop control of the pipe size, saving more than one million yuan in annual costs.
5. X-ray detection equipment
Deep detection capability
X-ray technology (such as X-rays and gamma rays) uses the material's attenuation difference to image the ray, which is particularly suitable for internal defect detection of thick-walled tubes (such as tubes for the nuclear industry). Its characteristics include:
High sensitivity: can identify micron-level pores and inclusions.
Data visualization: Generate cross-sectional diagrams, fluctuation trend diagrams, etc., to provide a basis for process optimization.
Challenges: The equipment cost is high and radiation protection is required, and it is mostly used for random inspections in key areas.
Conclusion
At present, stainless steel pipe inspection has formed a five-in-one technical system of "eddy current-ultrasound-infrared-diameter measurement-ray", covering full-dimensional quality control from surface to interior, from size to defects. In the future, with the integration of artificial intelligence and Internet of Things technology, detection equipment will further evolve towards intelligence (such as automatic defect classification), remoteness (cloud monitoring) and greenness (pollution-free process), providing stronger protection for industrial safety and efficiency.
