Nondestructive testing culture

Nondestructive testing -- the "quality guard" of modern industry 1

Nondestructive testing is an applied technical discipline based on modern science and technology. On the premise of not damaging the internal structure of the object being tested, it applies physical methods to detect the physical properties, state characteristics and internal structure of the object or surface, and check whether there is discontinuity (i.e., defect) inside the substance, so as to determine whether the object being tested is qualified. Then evaluate its applicability.

Nondestructive testing almost involves optics, electromagnetism, acoustics, atomic physics, computer, data communication and other disciplines in physical science, in metallurgy, machinery, petroleum, chemical industry, aviation, aerospace and other fields have a wide range of applications.

Without the application of nondestructive testing technology, it would be difficult to guarantee the quality of steel, machinery might stop running, airplanes would have difficulty taking off, rockets would have difficulty flying, cars might flip over on the road, trains might derail, oil and gas pipelines might leak, boilers and pressure vessels might explode... It can be said that in the application field of modern science and technology, no technology can have such a wide range of scientific basis and application field as nondestructive testing.

As one of the basic technologies of modern industry, nondestructive testing technology is playing an increasingly important role in ensuring product quality and engineering quality, and its reputation as "quality guard" has been widely recognized by the industry.

Nondestructive testing, as far as its own nature is concerned, focuses on the specific application of science and technology. Therefore, it is a technical subject with strong applicability and has strong operability or technology.

Whether the operation technology is skilled or not, to a large extent determines the accuracy of the test results. This technology is not only manifested in the specific operation (such as: ultrasonic probe movement), but also manifested in the movement of the detection machinery, automatic control, and the application of the computer. Therefore, it is not too much to call nondestructive testing a comprehensive applied technical discipline.

Nondestructive testing technology not only has profound scientific background, but also has rich cultural connotation. Nondestructive testing embodies the wisdom of modern science, shining the brilliance of modern culture, now

Generation civilization has made a contribution to nondestructive testing. As mankind enters the glorious 21st century, we should examine the cultural phenomenon of nondestructive testing from a higher perspective.

Second, the history of nondestructive testing culture

Since Roentgen, a German scientist, discovered X-ray in 1895, nondestructive testing has been used as an applied technical discipline for more than one hundred years. However, when we open the chapter of history, brush away the dust of the years, we will be surprised to find that the origin and development of nondestructive testing technology has a rich historical background.

Let's follow the long history, along with the clues of the development of physical science, to find the footprint of the growth of nondestructive testing discipline with a broader vision.

Our country is an ancient civilization in the world and has made a great contribution to the development of science and technology. Our ancient science and technology cultural heritage has many records applying non-destructive testing technology, from which we can see that our ancient time has a simple non-destructive testing science thought.

The physical knowledge of optics, mechanics and acoustics was recorded in Chinese works such as Kao Gong Ji and Mo Jing in pre-Qin period, so that the simple thought of nondestructive testing can be traced back to ancient times. More than 2500 years ago, in the Spring and Autumn period of the State of Qi, there was an important manual industry technology book "Kaogong Ji", which recorded the non-destructive testing method to control the quality of cast copper in the process of copper smelting: "In the form of casting gold, gold (copper) and tin, yellow and white followed; Yellow and white gas exhaustion, green and white second; Green and white gas exhaustion, green gas next, and then can be cast." This text accurately records that when copper is smelted, the smelting process is determined by observing the color of the flue gas, that is, the impurity volatilization in the smelted copper is judged by the different colors of the flue gas during smelting, so as to determine the time for copper water to come out.

This shows that our spring and autumn times have simple applications of non-destructive testing technology, which is similar to today's infrared measurement and control technology. In 400 BC, Mo Di (478 BC -- 392 BC) recorded and discussed the keyhole imaging and the relationship between light color and temperature in the Book of Mo.

During the Spring and Autumn period and the Warring States period, we found that the magnet has the properties of absorbing iron and guide. In the 3rd century BC, the ancient book "Han Feizi" recorded Siman (magnet stone guide phenomenon); "The Spring and Autumn Annals of the Lu Dynasty" recorded "kindness (magnetic) stone summons iron", which is perhaps the earliest record of magnetic attraction. In the 2nd century BC, Liu An (179 BC -- 122 BC) wrote a book called "Zhunanzi", which recorded such phenomena as the repulsion of artificial magnets and magnetic poles.

"On Heng" was written by Wang Chong (AD 2797) in the Eastern Han Dynasty. It records the physical knowledge of mechanics, heat, acoustics, magnetism and other aspects. The content is very rich. Wang Chong in "on balance" there is: "the person so speech appeal, air mouth throat, shake the tongue, a shea mouth, so can become a character. Compared with blowing Xiao Sheng, Xiao Sheng is broken. The more the qi is broken, the more the hand has nothing to do, the more it does not sound. The pipe of the husband's flute is swallowed by a Jew's mouth, and the hand is swallowed by a Jew's mouth." He also said: "One's conduct changes the distance between air and fish, and air should change with water."

It can be seen that he has realized that human voice is generated by air vibration, pointed out that the transmission of vibration should be through the medium, and compared the transmission of sound in the air with the transmission of visible water waves. This analogy is still applicable today when we talk about interference and diffraction of sound waves in ultrasonic testing.

Mengxi Pen Talk was written by Shen Kuo (1031 -- 1195), a statesman and scientist in the middle of the Northern Song Dynasty. It is an important work in the history of Chinese science, recording the discovery of geomagnetic declination, imaging principle of concave mirror and resonance phenomena.

"Mengxi Pen Talk" pointed out that "the Fang Fang sharpening the needle with a magnet can guide, but usually slightly east, not South Jeolla." It shows that Shen Kuo has found the magnetic declination Angle in the experiment. In addition to the general introduction of concave mirror imaging and pinhole imaging, the book also studied and explained the linear propagation of light, the refraction of light and the formation of rainbows. These principles are still applicable to magnetic and radiological testing today.

Zhao Youqin (1279 -- 1368), an experimental physicist in the Yuan Dynasty, wrote the New Book of the Revolutionary Image, which records his optical experiments and problems such as illumination, linear propagation of light, Angle of view and hole imaging. In the book, he made a more in-depth study and detailed description of optical phenomena, and used experiments to study keyhole imaging, and pointed out the rule of keyhole imaging. In his experiments, he showed that when light passes through a small hole, the resulting spot on a screen is always an image of something emitting light, regardless of the shape of the hole. When the hole is quite large, the shape of the spot obtained on the screen depends on the shape of the hole, the hole is square, and the hole is round. His explanation for this phenomenon is "a small is not enough for the body of the sun and the moon, with the shape of the sun, the moon and the circle, and its lack is lack." "Do a lot of niches for the sun and the moon." It shows that the pore imaging is related to the pore size. After a series of careful observation experiments, Zhao Youqin pointed out: "where the view near the orificket narrow, far orificket wide; Candle far orifice view is also narrow, candle near orifice view is also wide.

Wide is light, narrow is strong. Candle is near and light decline, the scene is also light, candle is far and light rich, the scene is also strong. By observing it, candle also, light also, orifice also, scenery also, four ups and downs, all when the theorist also." This argument is exactly the same as the explanation of geometric unarticulation in X-ray testing today.

It is an ancient test to determine the internal structure of objects based on changes in sound frequency. In the Ming Dynasty Song Yingxing's book "Tiangong Kaiwu" recorded as follows: "After the kettle is finished, try to knock it, the sound is as good as wood, the sound is bad, the iron is not ripe, it is easy to damage." This ancient sound detection method is still widely used in quality detection today.

The ancient science and technology of our country shines like the stars which are shining brightly. Only in modern times did our science and technology fall behind due to the corruption of the Qing Dynasty and invasion of foreign imperialist dynasty.

The development history of world physics can be divided into three stages: ancient physics, classical physics and modern physics.

Ancient knowledge of physics was interwoven with other scientific and technological knowledge and recorded. In the 4th and 5th centuries BC, Aristotle of ancient Greece wrote about atomism of matter and mechanics.

Archimedes discovered the buoyancy of water. In the third century BC Euclid explained the linear propagation of light and the law of reflection. Physics knowledge such as optics, mechanics and acoustics was recorded in a large number of scientific historical materials, such as the "Khao Gong Ji" and "Mo Jing" in the Pre-Qin period and the "Mengxi Pen Talk" in the Northern Song Dynasty.

During the long Middle Ages from the 5th century to the 14th century in Europe, the feudal theocratic social system severely confined the field of thought and culture, and the development of natural science was extremely slow. In the late feudal society of Europe, from the 14th and 15th centuries, the capitalist mode of production gradually developed. In the anti-feudalism and anti-theology struggle of the bourgeoisie, the revolution of natural science first made a breakthrough in astronomy, and the heliocentric theory of Copernicus was defended and developed in the fierce struggle with the church, which started the revolution of modern natural science.

After the 17th century, the British scientist Newton discovered the three laws of mechanics, on this basis to establish a complete theoretical system of physics classical physics. In 1687, Newton published the Mathematical Principles of Natural Philosophy, which established classical mechanics. From the 17th century to the 19th century, the development of classical physics has been rapid: Huygens put forward the theory of light wave, derived the linear propagation of light and light reflection, refraction law, and explained the phenomenon of birefringence; Joule and Helmholtz et al. did thermodynamics and molecular physics; Fuchlin proposed the concept of "positive" and "negative" electricity. Then we have Coulomb's law, Faraday's law; Maxwell developed a theory of electromagnetic fields; Huygens Fresnel principle explains the linear propagation and refraction of waves. Oster discovered that electric currents deflect magnetic needles around them; Joule and Lenz discovered the law of thermal effect when an electric current passes through a conductor, which is called Joule Lenz's law. Doppler found that the wave source generated by vibration and the frequency of the wave will appear different phenomenon, called Doppler effect. Foucault found that in a rapidly changing magnetic field, an induced current would be generated in the body of the conductor. This current would move like a vortex, which is called eddy current. Rayleigh theoretically analyzes the scattering phenomenon of light, which is called Rayleigh scattering. Rayleigh's Principles of Acoustics laid the foundation for modern acoustics. The Curie brothers discovered that when quartz crystal is under pressure, its surface will produce electric charge, the amount of charge is proportional to the pressure phenomenon, called the piezoelectric effect; In 1895, German scientist Roentgen discovered X-rays, which ushered in a revolution in modern physics. The discovery of uranium's radiation by Becquerel in 1896 marked the beginning of atomic physics. In 1898, the Curies discovered radium after studying radioactive substances; In 1899, Rutherford experimentally identified two types of radiation: alpha and beta; In 1900, Villard discovered that there was another type of radiation that was not affected by magnetic fields, called gamma rays.

In 1905, Einstein created the special theory of relativity, which revealed the essential connection between time and space, put forward the light quantum theory, explained the photoelectric effect phenomenon, revealed the wave and particle duality of microscopic objects, caused a major change in the basic concept of physics, and opened a new era of physics. In 1915, Einstein established the general theory of relativity, which marked that physics entered a new era of modern physics.

From ancient physics, classical physics to modern physics, from Archimedes buoyancy, Newton mechanics to Einstein's theory of relativity, this string of shining wisdom brilliant scientists and their famous names and their achievements, so far that we are engaged in nondestructive testing of science and technology workers feel infinite admiration. Every principle and effect of physics appear in today's Nondestructive Testing textbook, which makes us still feel esoteric when we read them, and then when they are translated into specific testing methods, makes us feel very friendly and easy to master testing technology.

The development of physics breeds rich cultural and historical deposits of nondestructive testing, and physics is the cradle of nondestructive testing technology. Today, review the history of nondestructive testing culture, like a key to enlighten the hall of nondestructive testing science and technology knowledge, give us wisdom and strength, let us bravely to meet the challenge of modern science and technology, to make a contribution to modern industry.

Third, the establishment of modern nondestructive testing system and the formation of nondestructive testing culture

With Roentgen's discovery of X-ray in 1895, nondestructive testing, as a multidisciplinary technology, began to enter the practical application field of industrial mass production.

In 1900, French customs began to use X-ray inspection articles. In 1922, the United States established the world's first industrial X-ray laboratory to check casting quality with X-ray, which has been widely used in military industry and machinery manufacturing and other fields. X-ray detection is still an important means of quality control for many industrial products.

In 1912, ultrasonic detection technology was first used in navigation to detect icebergs on the sea surface. In 1929, ultrasonic technology was used to detect product defects. It is still the main detection means for boiler pressure vessels, railway tracks and important mechanical products.

As early as in the Spring and Autumn Period, the Lu Shi Spring and Autumn Period had the saying "kind (magnetic) stone summons iron", but the magnetic detection of industrial products was only in the early 20th century. In the 1930s, the magnetic particle detection method was used to detect the crank and other key parts of vehicles. Later, the magnetic particle detection method was widely used in steel structural parts, which made the magnetic particle detection widely used in the surface detection of various ferromagnetic materials.

Capillary phenomenon is a common phenomenon in soil water evaporation. With the emergence of large-scale industrial production, the principle of capillary phenomenon has been successfully applied to the detection of opening defects of metal and non-metallic materials. Its sensitivity is comparable to that of magnetic particle detection, and its biggest advantage is that it can detect non-ferromagnetic materials.

The classical law of electromagnetic induction and the discovery of eddy current charge skin effect have promoted the generation of modern eddy current detection methods for conductive materials. In 1935, the first eddy current detection instrument was successfully researched. In the early 1950s, German scientist Horst published a series of papers on electromagnetic induction, which opened a new chapter of modern eddy current detection.

In the middle of the 20th century, under the promotion of modern industrial production, a nondestructive testing system was established, which was represented by five conventional testing methods: radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), penetrant testing (PT) and electromagnetic testing (ET).

With the continuous development of modern science and technology and mutual penetration, new nondestructive testing technologies are emerging and new nondestructive testing methods are emerging endlessly. A relatively complete nondestructive testing system has been established, covering most fields of industrial large-scale production. During the establishment of nondestructive testing system, a complete culture of nondestructive testing has been formed gradually.

The cultural connotation of nondestructive testing is as follows: a complete theory of nondestructive testing is established on the basis of modern physics and modern physics; Established a high quality nondestructive testing professional team, engaged in nondestructive testing theory research and practical testing application; With a large number of non-destructive testing instruments, equipment manufacturers; Nondestructive testing has been fully used in various fields of industrial production, and plays an important role in the quality control and quality assurance of industrial products and major projects. Modern industrial important products have the characteristics of "high temperature, high pressure, high speed, high stress", if there is no non-destructive inspection