Non-Destructive Testing (NDT)
HISTORY OF NON-DESTRUCTIVE TESTING
NDT/NDE has been practiced for decades. Over the years, technological advances spurred rapid developments in techniques and instrumentation. It is impossible to identify exactly when this science began; however, we know that it has been evolving for centuries. For example, blacksmiths used a sonic technique (listening to a ring of different metals) to shape them as desired.
The roots of modern NDT/NDE began prior to the 1920s, but awareness of different methods truly came in the 1920s. During this era there was an awareness of some of the magnetic particle tests (MT) and X-radiography (RT) [in the medical field].
In the early days of railroad, a technique referred to as the “oil and whiting test,” was used and staged the ground for the present day penetrant test (PT). As well, there were some basic principles of eddy current testing (ET) and archaic gamma radiographic techniques. But the majority of the methods that are known today didn’t appear until late in the 1930s and into the early 1940s.
Pre World War II, designers had to engineer with unusually high safety factors for many products, such as pressure vessels and other complex components. Discontinuities and imperfections [relative to lifecycle] became a concern. Catastrophic failures due to product inadequacies brought concern for quality to the forefront. In 1941, the American Industrial Radium and X-ray (now the American Society for Nondestructive Testing) was formed marking the beginning of organization of this field.
A key period in the history and development of nondestructive testing came during and after the Second World War. During the earlier days, the primary purpose was the detection of defects. The war expedited the development of techniques that allowed higher-integrity, more cost- effective production.
From the late 1950’s to present, NDT/NDE has seen exponential advancement. The evolution of NDT/NDE is directly related to safety, the development of the new materials, and the demand for greater product reliability. The changes that have occurred in construction, aerospace, nuclear applications, manufacturing and space exploration would not have been possible without the application of NDT and NDE.
- 1831 − Michael Faraday discovered the principles of electromagnetic induction, the basis that eventually became the principles of eddy current testing (ET).
- 1847 − James Precott Joule discovered the methods of exciting ultrasound. [1880 by Pierre Curie and his brother Paul Jacques].
1850 − 1879
- 1854 − A boiler at the Fales and Gray Car Works (Hartford, CT) explodes, killing 21 people and seriously injuring 50. The explosion destroyed the boiler room and an adjoining blacksmith shop, and it severely damaged the main building.
- 1857 − Polytechnic club was founded as a direct result of 1854 boiler explosion.
- 1864 − The State of Connecticut passes a law (Boiler Inspection Law) requiring annual inspection (in this case visual) of boilers. Basically, twelve men who had an interest in boilers met periodically and studied the problems relating to steam boilers.
- 1865 − The “Sultana,” a Mississippi side-wheeler with two tall stacks was steaming along above Memphis when three of her four boilers exploded. The actual cause for this catastrophic explosion was never determined. The Sultana was carrying between 1200 and 1600 people.
- 1866 − The Connecticut legislature approved an act of incorporation of Hartford Steam Boiler Inspection and Insurance Company. The basis of the insurance was an inspection of the boiler as a prerequisite to issuing an insurance policy.
- 1867 − Policy Number 1 was written by Hartford Steam Boiler on three horizontal tubular boilers for a face value of $5,000. The premium was $60.
- 1868 − S.M. Saxby, an Englishman, attemps to find cracks in gun barrels by magnetic indications.
- 1879 − E. E. Hughes performs the first recorded eddy current test; he was able to distinguish the difference between various metals by noting a change in excitation frequency.
1880 − 1899
- 1880 − The “Oil and Whiting” method of crack detection is used in the railroad industry. This precursor to modern liquid penetrant tests was used until the 1920s when the method was replaced by the upcoming MP-technique. The method included a subject soaked in thinned oil, painted with a white coating that dries to a powder. Oil seeping out from cracks turned the white powder brown, allowing the cracks to be detected.
- 1895 − Wilhelm Conrad Röntgen discovers “An Unknown Kind of Radiation”; what are now known as X-rays. The medical industry saw benefits of the use of this new substance; however, did not fully understand its risks.
1900 − 1919
- 1901 − Röntgen received the Nobel-prize for physics.
- 1903 − Mme. Curie with her husband, Pierre Curie, and Henri Becquerel received the Nobel-prize for physics. Mme. Curie discovered that radiation testing can also be carried out with radioactive isotopes.
- 1911 − The first boiler code committee was formed and the first code was developed during the years of 1911 to 1914.
- 1912 − The first application of ultrasonic testing was proposed after the Titanic sunk. Richardson, an Englishman, claimed the identification of icebergs by ultrasound in his patent applications. During the same year, Chilowski and Langevin of France began development to detect submarines by ultrasound during World War I.
- 1915 − The first boiler code was published. Visual Testing (VT) was the initial method of nondestructive testing. The code will have a major impact on the growth and application of nondestructive testing.
1920 − 1929
- 1920 − Dr. H. H. Lester begins development of industrial radiography for metals. Dr. Lester was directed to develop X-ray techniques for examination of castings, welds, and armor plate by the Army. He began his work at the Watertown Arsenal in Boston, Massachusetts. His work served as the foundation for future development of the radiographic test method using X-ray sources.
- 1924 − Dr. Lester uses radiography to examine castings to be installed in a Boston Edison Company steam pressure power plant.
- 1926 − The first electromagnetic eddy current instrument is available to measure material thicknesses.
- 1928 − Magnetic induction system to detect flaws in railroad track developed by Dr. Elmer Sperry and H.C. Drake.
- 1929 − Magnetic particle methods and equipment are created (derivative of early electromagnetic conduction and induction experiments preformed by Professor F. V. Deforest F.B. Doane.) Later this would be used to form the Magnaflux Corporation. In the same year, Sokolov (Russian) proposed to use ultrasound for testing castings.
1930 − 1939
- 1930 − Richard Seifert (Germany) realizes technical X-ray applications. He used current medical techniques and applied them to other applications through the cooperation of welding institutes. He expanded the family business with this new technology, which ultimately received competition from larger corporations, such as Siemens and Phillips.
- 1930s − Robert F. Mehl demonstrates radiographic imaging using gamma radiation from radium. This application can examine thicker components than the low-energy X-ray machines available at the time.
- 1932 − Giraudi (Italian) becomes the first European to build a magnetic particle crack detector, named “Metalloscopio”. Berthold and Vaupel (Germany) applied MP-technique to welded constructions and the swinging field MP-testing was invented. E.A.W. Müller (Berlin) designed MP-testing machines for Siemens. Seifert-representative Karasek (Prague) began with similar production.
- 1933 − Rudolf Berthold and Otto Vaupel (Germany) apply radioactive isotopes [initially used for medical applications] to welded joints.
- 1934 − The Magnaflux Corporation was formed to promote the use of magnetic principles for industrial NDT application.
- 1935 − Betz, Doane, and DeForest begin liquid penetrant test development. Their work is recognized around 1940.
- 1935 − H.C. Knerr, C. Farrow, Theo Zuschlag, and Fr. F. Foerster begin developing Eddy current instruments. Their work is recognized in the 1940s.
- 1937 − Pohlman (Berlin) utilized an image-cell to indicate the differences of ultrasound-energy, similar to an X-ray image-screen.
1940 − 1949
- 1940s − The first million volt X-ray machines were introduced by General Electric. In the early 1940s through World War II, further developments resulted in better and more practical eddy current instruments. Industrial use of ultrasonic testing started simultaneously in three countries. Floyd Firestone (USA), Donald O. Sproule (GB) and Adolf Trost (Germany) had no knowledge of each other. Trost invented the so-called “Trost-Tonge”; Sproule invented double-crystal probes; and, Firestone was the first to realize the reflection-technique. Sproule and Firestone found industrial partners for their instruments: Kelvin-Hughes and Sperry Inc.
- 1941 − The American Industrial Radium and X-ray Society was founded. This later would become the American Society for Nondestructive Testing.
- 1948 − Eddy Current Testing has old roots, as well. The French Dominique Arago discovered the phenomenon during the first half of the 19th century. The principle was explained by and named after Leon Foucault. Many proposals for application were made until Friedrich Förster brought this method to industrial use. He had worked for the Kaiser-Wilhelm-Institute since 1933, and there he developed instruments for measuring conductivity and to sort out mixed-up ferrous components. In 1948 he founded his own company in Reutlingen which grew up with Eddy current testing (ET). Institut Dr. Förster became market-leader worldwide for many decades.
- 1949 − In Germany in 1949, two persons received information about the Firestone-Sperry-Reflectoscope by publications in technical papers: Josef Krautkrämer in Cologne and Karl Deutsch in Wuppertal. Both started developments – without knowledge of each other. Josef Krautkrämer and his brother, Herbert, were physicists, working in the field of oscilloscopes. They could develop ultrasonic instruments alone. Karl Deutsch, a mechanical engineer needed a partner to assist with the electronics and found Hans-Werner Branscheid who had obtained technical experience in radar-technique during the war. Within only one year, small companies could present their UT-flaw-detectors, starting a competition still existing today.
1950 − Present
- 1950 − J. Kaiser introduces acoustic emission as an NDT method
- 1950s − The use of ultrasonic testing is expanded to compliment radiography as a source of internal inspection. Japan developed ultrasound techniques to detect gallstones, breast masses, and tumors and presented their findings to the international medical community.
- 1976 − ASNT inaugurated its NDT Level III program in 1976 with certification offerings in five NDT methods. Over the years, ASNT has certified over 5,000 individuals from more than 50 countries as ASNT NDT Level IIIs and has expanded the certification program to include 11 NDT methods. ASNT is the single largest certifying body of Level III personnel today and the ASNT NDT Level III certificate remains the most respected and widely accepted NDT certification throughout the world.
Current NDT methods are: Acoustic Emission Testing (AE), Electromagnetic Testing (ET), Laser Testing Methods (LM), Leak Testing (LT), Magnetic Flux Leakage (MFL), Liquid Penetrant Testing (PT), Magnetic Particle Testing (MT), Neutron Radiographic Testing (NR), Radiographic Testing (RT), Thermal/Infrared Testing (IR), Ultrasonic Testing (UT), Vibration Analysis (VA) and Visual Testing (VT).
The six most frequently used test methods are Visual Testing (VT), Magnetic Particle Testing (MT), Liquid Penetrant Testing (PT), Radiographic Testing (RT), Ultrasonic Testing (UT) and Acoustic Emission Testing (AET). Each of these test methods will be described here, followed by the other, less often used test methods.
The document was created: 19. 10. 2021 14:26:38
Prepared under project CZ.1.07/2.2.00/28.0020 Innovation of study programs FA MENDELU towards internationalization of study