A long stainless steel object micro-crack infrared thermal imaging detection device

Abstract

The utility model belongs to nondestructive testing technical field, specifically disclose a kind of long stainless steel article microcrack infrared thermal imaging detection device, including power, computer, slide rail and the support of installation in the long stainless steel article long axis direction movement of slide rail;Support is fixed with thermal imager and hot hair dryer;Power is connected with hot hair dryer, computer and thermal imager communication connection;The field of view of thermal imager is towards long stainless steel article surface, and the air outlet of hot hair dryer is opposite to long stainless steel article surface.This utility model innovatively changes detection mode from traditional penetration detection to infrared thermal imaging uniform scanning detection, with the advantages of convenient operation, more crack types can be detected (including opening and micro-closed crack), environment-friendly, high detection efficiency, effectively solves the pain points of complicated penetration detection process, serious pollution and insufficient detection capability for micro-closed defects.

Description

Technical Field

[0001] This utility model belongs to the field of non-destructive testing technology, specifically relating to an infrared thermal imaging detection device for microcracks in long stainless steel objects. Background Technology

[0002] Surface microcracks are a common type of defect in the manufacturing and service of long stainless steel workpieces. If they are not detected in time, they may lead to fatigue propagation or even fracture failure, posing serious safety hazards.

[0003] Currently, penetrant testing is one of the most widely used methods for surface defect detection. Its basic principle involves coating the workpiece surface with a penetrant, allowing it to penetrate open defects through capillary action. Excess penetrant is then removed, and a developer is applied to absorb the remaining penetrant within the defect, thus forming a defect indication under visible light. However, penetrant testing has several significant drawbacks: First, it has low efficiency, requiring multiple steps including pre-cleaning, penetrant penetration, cleaning, development, and observation, which is time-consuming and difficult to meet online or batch testing needs. Second, it is complex to operate, requiring highly skilled operators; any improper operation, such as over-cleaning or uneven development, can lead to missed or misjudged defects. Furthermore, penetrants and developers often contain volatile organic solvents and dyes, easily generating waste liquid and exhaust gas during the testing process, causing serious environmental pollution and contradicting the trend of green manufacturing. Additionally, this method is only applicable to open defects, with limited ability to detect closed or micro-closed cracks, and it cannot provide defect depth information. In contrast, infrared thermal imaging technology, as a non-contact, full-field imaging detection method, has advantages such as speed, visualization, and environmental friendliness, theoretically providing a better solution to replace penetrant testing. It can detect not only open defects but also has the potential to detect micro-closed cracks, while avoiding the use of chemical reagents, aligning with the trend of green manufacturing. However, in practical applications on long stainless steel workpieces, it still faces the problem of insufficient scanning coverage. Traditional infrared thermal imagers mostly perform fixed-point shooting, making it difficult to achieve continuous and uniform scanning of long workpieces such as pipes and bars, easily missing axial cracks. Utility Model Content

[0004] The purpose of this invention is to solve the problem that traditional infrared thermal imagers mostly take fixed-point shots in practical applications of long stainless steel workpieces, making it difficult to achieve continuous and uniform scanning of long workpieces such as pipes and bars, and easily missing axial cracks. Therefore, an infrared thermal imaging detection device for microcracks in long stainless steel objects is proposed.

[0005] The technical solution of this utility model is as follows: an infrared thermal imaging detection device for microcracks in a long stainless steel object, including a power supply, a computer, a slide rail, and a bracket installed on the slide rail; a thermal imager and a hot air blower are fixed on the bracket; the power supply is connected to the hot air blower, and the computer is communicatively connected to the thermal imager; the field of view of the thermal imager is oriented towards the surface of the long stainless steel object, and the air outlet of the hot air blower is opposite to the surface of the long stainless steel object.

[0006] Preferably, the thermal imager has a resolution ≥640×480, thermal sensitivity ≤0.05K, and frame rate ≥30Hz.

[0007] Preferably, the outlet temperature of the hot air blower is adjustable from 100℃ to 300℃, and the air speed is set from 0.5m / s to 5m / s.

[0008] Preferably, the bracket is used to move the thermal imager and the hot air blower along the long axis of the long stainless steel object, the moving speed of the bracket is set to 1–10 cm / s, and the positioning accuracy of the bracket is set to ≤±0.1 mm.

[0009] The beneficial effects of this utility model are: This invention achieves continuous, non-contact inspection of long stainless steel workpieces through a sliding rail scanning and thermal imaging synchronous design. It has a simple structure, high efficiency, and is suitable for rapid screening and quality assessment of pipes, bars and other components in industrial settings. Attached Figure Description

[0010] Figure 1 The diagram shows a schematic of an infrared thermal imaging detection device for microcracks in long stainless steel objects.

[0011] Figure labeling: 1-Power supply, 2-Computer, 3-Thermal imager, 4-Hot air blower, 5-Slide rail, 6-Long stainless steel object. Detailed Implementation Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the present invention, and are not intended to limit the scope of the present invention.

[0012] Example 1: like Figure 1 As shown, an infrared thermal imaging detection device for microcracks in a long stainless steel object includes a power supply 1, a computer 2, a slide rail 5, and a bracket mounted on the slide rail 5; a thermal imager 3 and a hot air blower 4 are fixed on the bracket; the power supply 1 is connected to the hot air blower 4, and the computer 2 is communicatively connected to the thermal imager 3; the field of view of the thermal imager 3 is oriented towards the surface of the long stainless steel object 6, and the air outlet of the hot air blower 4 is opposite to the surface of the long stainless steel object 6.

[0013] In this embodiment, the thermal imager 3 has a resolution ≥640×480, thermal sensitivity ≤0.05K, and frame rate ≥30Hz.

[0014] In this embodiment, the outlet temperature of the hot air blower 4 is adjustable from 100℃ to 300℃, and the wind speed is 0.5m / s to 5m / s.

[0015] In this embodiment, the bracket is used to drive the thermal imager 3 and the hot air blower 4 to move along the long axis of the long stainless steel object 6. The moving speed of the bracket is set to 1–10 cm / s, and the positioning accuracy of the bracket is set to ≤±0.1 mm.

[0016] This invention proposes an infrared thermal imaging detection device for microcracks in elongated stainless steel objects. By employing a sliding rail to drive the thermal imager and thermal excitation source in a synchronous, uniform scanning motion, it achieves uniform heating and continuous imaging of the workpiece surface, improving the accuracy and efficiency of crack detection. While retaining the advantages of non-contact and rapid imaging in infrared thermal imaging, this method overcomes its key limitations in detecting microcracks on stainless steel surfaces, providing a green, efficient, and automated solution to replace traditional penetrant testing.

[0017] Example 2: This invention provides an infrared thermal imaging detection method for microcracks in elongated stainless steel objects. It relies on the infrared thermal imaging detection device for microcracks in elongated stainless steel objects provided in this embodiment. Based on infrared thermal imaging technology combined with a uniform scanning mechanism, it achieves rapid localization of surface microcracks. The thermal imager 3 and the hot air blower 4 move synchronously via a slide rail 5 to uniformly heat the surface of the elongated stainless steel object 6, while simultaneously acquiring real-time temperature field change data. After the thermal image is transmitted to the computer 2, abnormal areas are identified using a temperature gradient algorithm, thereby determining the location of the microcracks. This method has the advantages of being non-contact, easy to operate, and highly efficient, and is suitable for online non-destructive testing of elongated workpieces such as stainless steel pipes and bars. Specifically, the method involves fixing the elongated stainless steel object 6 on the detection platform and adjusting the focal length of the thermal imager 3 so that its field of view covers the width of the elongated stainless steel object 6. Then, slide rail 5 is activated, and the moving speed is set to v=3cm / s. The hot air blower 4 is set to a constant outlet temperature (e.g., 150℃), causing the bracket to move uniformly along the axis of the long stainless steel object 6. The hot air blower 4 continuously heats the surface of the long stainless steel object 6. Thermal imager 3 synchronously acquires thermal images at a frame rate of 30Hz and transmits the data to computer 2 in real time. After receiving the image sequence, computer 2 executes a temperature gradient analysis algorithm to analyze the image sequence and identify areas of abnormal temperature. Finally, based on the position information recorded by the slide rail encoder, the center coordinates of the crack are output, completing the detection. The temperature gradient analysis algorithm specifically involves: performing spatiotemporal fusion on the thermal image sequence to generate a three-dimensional matrix of temperature-position-time; calculating the longitudinal temperature gradient ∇ of each frame image along the moving direction of slide rail 5. T y If the longitudinal temperature gradient of a certain region is ∇ T y If the abnormality persists (exceeding the set threshold Kth and lasting for more than 3 frames), it is determined to be a suspected crack area.

[0018] This method, through the simultaneous design of sliding rail scanning and thermal imaging, enables continuous, non-contact inspection of long stainless steel objects. It features a simple structure, high efficiency, and is suitable for rapid screening and quality assessment of components such as pipes and bars in industrial settings.

[0019] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of this invention, and should be understood that the scope of protection of this invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on these technical teachings disclosed in this invention without departing from the essence of this invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A device for detecting microcracks in elongated stainless steel objects using infrared thermal imaging, characterized in that, Includes a power supply (1), a computer (2), a slide rail (5) and a bracket mounted on the slide rail (5); a thermal imager (3) and a hot air blower (4) are fixed on the bracket; the power supply (1) is connected to the hot air blower (4), and the computer (2) is connected to the thermal imager (3) in communication; the field of view of the thermal imager (3) is directed toward the surface of the elongated stainless steel object (6), and the air outlet of the hot air blower (4) is opposite to the surface of the elongated stainless steel object (6).

2. The infrared thermal imaging detection device for microcracks in elongated stainless steel objects according to claim 1, characterized in that, The thermal imager (3) has a resolution of ≥640×480, a thermal sensitivity of ≤0.05K, and a frame rate of ≥30Hz.

3. The infrared thermal imaging detection device for microcracks in elongated stainless steel objects according to claim 1, characterized in that, The outlet temperature of the hot air blower (4) is adjustable from 100℃ to 300℃, and the wind speed is set from 0.5m / s to 5m / s.

4. The infrared thermal imaging detection device for microcracks in elongated stainless steel objects according to claim 1, characterized in that, The bracket is used to move the thermal imager (3) and the hot air blower (4) along the long axis of the long stainless steel object (6). The moving speed of the bracket is set to 1–10 cm / s, and the positioning accuracy of the bracket is set to ≤±0.1 mm.

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