JPS63150662A - Flaw detecting method for steel material - Google Patents

Abstract

PURPOSE:To improve inspection accuracy by carrying out a magnetizing fluorescent treatment for the surface of a body to be measured, projecting and scanning an ultraviolet-ray laser beam in a spot, and measuring generated fluorescent light by a detector. CONSTITUTION:The surface of the body W to be measured is coated with a magnetic powder fluorescent material and then an excessive magnetic powder fluorescent agent is cleaned away. Then the ultraviolet-ray laser beam 3 which is projected by a laser oscillator 2 is converged by a converging optical system 4 into a spot matching with the size of a defect and projected and scanned on the surface of the body W to be measured by a scanner 5, and its reflected light is converged by the convergent optical system 6 by the detector 8. Then the light is photodetected by a photoelectric transducer 7 and transduced into an electric signal, which is compared by a control part with preset intensity corresponding to the size of the defect to measure whether or not the defect is present, and its position and quantity.

Description

[Detailed Description of the Invention] [Object of the Invention] 1. The present invention is a non-destructive inspection method for inspecting defects in steel materials, and is a method for automating inspection, saving labor, and This invention relates to a method for detecting defects in bonded materials in order to improve reliability and quality.

Traditionally, fluorescent magnetic particle testing has been widely used to inspect defects in the manufacturing process of steel products (materials or processed products), but it has not been automated and relies on visual judgment. At present, there are many defects in the steel product, and visual inspection methods cannot distinguish between scratches and intact parts if the defects in the steel product are minute, covered with black scale, or the surface is rough and uneven. Because there is little difference in fluorescence intensity, this results in various differences in inspection judgments, and in turn, machines using the steel product cannot detect defects during the inspection of the steel product, resulting in incorrect predictions. There was a risk that it could lead to a major accident outside.

In addition, since the above inspection method uses an ultraviolet lamp, it is difficult to focus the lamp light into a spot, and it can only obtain a small energy density compared to a laser, which makes it difficult to distinguish between scratches and intact areas. Because the difference in fluorescence intensity is small, optical detection is difficult, and inspection work must be done in a dark room, which creates a poor inspection atmosphere and can have negative effects on the human body.
In addition, according to an inspection method that detects reflected laser light without using fluorescent magnetic particles, it is possible to detect defects in iron and copper products when they are minute, covered with black scale, or when the surface is rough and uneven. However, the contrast between the reflected light between the scratched area and the undamaged area is not clear due to diffused reflection, making optical detection difficult.

The present invention aims to eliminate the above-mentioned shortcomings, such as the limitation of inspection accuracy and oversight of defective parts due to human error in judgment when inspecting defects in iron pot products by visual inspection. The present invention aims to provide a method for detecting defects in steel materials that enables automation, labor saving, and improved reliability and quality.

[Structure of the invention]

In view of these points, the present invention, which is designed to measure the world's A steel material designed to detect defects in DJ treasures by concentrating the fluorescence generated by fluorescent magnetic particles gathered at scratches on the surface, measuring it with a detector, and electrically processing the output signal from the detector. It is an object of the present invention to provide a defect detection method to eliminate the above-mentioned drawbacks.

The present invention has the above-mentioned configuration, performs magnetized fluorescent treatment on the surface of the steel material to be measured, concentrates the magnetic powder fluorescent material on the defective location, and projects an ultraviolet laser in the form of a spot on the surface of the steel material. After scanning, the detector focuses the fluorescence from the magnetic powder that has been fired into the scratches on the surface of the steel material, and the output signal proportional to the intensity of the reflected light is compared with the preset intensity in the control unit. The presence, location, and count of defects are detected using the following methods.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a detection section, and the radiation output section 1 is placed on the optical path of the ultraviolet laser 3 emitted from the laser oscillator 2.
A condensing optical system 4 for condensing the light is disposed, and a scanner 5 is disposed at a position where the condensed ultraviolet laser 3 is projected and scanned onto the surface of the object M and the treasure W.

A detector 8 comprising a condensing optical system 6 and a photoelectric conversion element 7 is disposed at a position where the reflected light from the object W to be measured is received.

Reference numeral 9 denotes a magnetization fluorescence processing unit which is a mechanism for applying a magnetic powder fluorescent material to the object W to be measured and magnetizing it, and 10 a treasure W to be measured.
The laser oscillator 2, the condensing optical system 4, and the scanner 5 are the magnetization cleaning processing unit of the mechanism that cleans the magnetic powder fluorescent material attached to the surface of the object W other than the defective parts on the surface of the object W. The number of detectors 8 can be set to be singular or plural depending on the shape of the treasure W to be stolen.

Next, to explain the method for detecting defects in steel materials according to the present invention, the object W to be measured is transferred to the magnetization fluorescence processing section 9.
The surface of the object to be measured W is subjected to magnetization fluorescence treatment, and the ultraviolet laser 3 irradiated from the laser oscillator 2 is made to form a spot according to the size of the defect using the condensing optical system 4. The reflected light is focused by the condensing optical system 6 of the detector 8, received by the photoelectric conversion element 7, and converted into an electrical signal.The resulting output signal is sent to the control unit. The presence, location, and number of defects are detected by comparing the intensity with a preset intensity corresponding to the size of the defect.

The above inspection work is carried out by moving the object W to be measured through a magnetization fluorescence processing section 9, a magnetization cleaning processing section 10, and an inspection section 1 using a mechanical drive mechanism.
By controlling and implementing the related operations, it is also possible to assemble an automatic flaw detection device for detecting defects in the object W to be measured.

C. Effects of the Invention] In short, the present invention performs magnetization fluorescence treatment on the surface of the object W to be measured, and projects and scans the ultraviolet laser 3 in the form of a spot on the surface of the object W to be measured, thereby removing scratches on the surface. Fluorescence generated from the collected fluorescent magnetic particles is focused and measured by the detector 8, and the output signal from the detector 8 is electrically processed to detect defects in the object W to be measured. In inspection for defects, there is less variation in inspection results depending on the skill level of the inspector in visual judgment, and there are fewer defective products due to overlooked defects, etc., and it is much more effective than visual judgment, especially when it comes to discovering minute defects. Since accuracy is improved and inspection can be performed continuously, inspection time can be shortened without requiring the level of skill of inspectors, and automation and labor saving as well as reliability and quality can be significantly improved. Its practical effects, such as tightening, are enormous.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic block diagram of the defect detection method for E material according to the present invention, and FIG. 2 is a configuration diagram of the main parts of the detection section. 3 UV lasers 8 detectors Figure 1 2nd flash

Claims (1)

[Claims] Applying magnetization fluorescence treatment to the surface of the object to be measured, projecting and scanning an ultraviolet laser in the form of a spot on the surface of the object to be measured, concentrating the fluorescence generated from the fluorescent magnetic particles gathered at the scratches on the surface, 1. A method for detecting defects in a steel material, the method comprising detecting defects in an object to be measured by measuring with a detector and electrically processing an output signal from the detector.