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Magnetic Particle Testing History

Written by Administrator
Monday, 01 June 2009 14:38

By Pierre CHEMIN and Patrick DUBOSC

June 2008
Completed and updated in December 2014

Ancient Greece Several millenniums B.C. Greeks discover magnetism in a mineral they call magnetite. The name "magnetite" comes from MAGNETOS ("the big mountain"), a Greek mountain rich in this mineral.
Ca 1000 Chinese discover the Earth magnetism and the compass.
1269 Pierre de Maricourt, a French man, writes the Epistola de Magnete (Letter about Magnetism) which deals with the basic laws of magnetism and the properties of magnets.
XVIth Century William GILBERT, a doctor of ELISABETH I of England, shows that a uniformly magnetized globe can produce a magnetic field in two poles.
1777 The French physicist Charles Augustin de COULOMB discovers that “the magnetic forces of attraction and repulsion are directly proportional to the strength of the poles and inversely proportional to the square of the distance from them.”
XIXth Century BERGMANN (?-?), BECQUEREL (1788-1870) and FARADAY (1791-1867) discover that any material, including liquids and gasses react to magnetism, but that only few do so to a noticeable extent.
1800 Alessandro VOLTA invents the electric battery and for the first time, sees the properties of the electric current that AMPÈRE will call "magnetic emanations".
1821 Hans Christian OERSTED discovers that an electric current flowing through a wire makes a nearby-compass needle to deflect. This is the electromagnetism.
1826 The French physicist Andre-Marie AMPÈRE discovers electrodynamics. He describes the forces that two parallel conductors carrying currents electrical exert on each other. If the current direction is the same in both conductors, they attract, if the current flows in opposite directions, the conductors repel. He also describes the relationship between the strength of the current and the corresponding magnetic field.
1831 Michael FARADAY discovers the electromagnetic induction.
1833 The first magnetometer is invented by Carl Friedrich GAUSS.
1868 S.H. SAXBY, an Englishman, describes in the journal Engineering the detection of longitudinal cracks in tubes using a magnetized needle, thus without magnetic particles.
Putting the tube in the East-West direction and making it turn while maintaining the needle at a constant distance, he sees that a crack produces a distortion of the magnetic field induced in the part by the Earth magnetic field, and as a result, a deviation of the compass needle. This very weak effect was probably improved using a permanent magnet. He called this process "damage-free inspection".
The earliest known use of magnetism to check a part. Flaws are found on magnetized gun barrels by moving a compass along the length of the barrel.
1879 The American HERING uses this technique on railroad rails.
The probe invented by the North American physicist E.H. HALL (1855-1938) is widely used in cracks detection.
1906 C.W. BURROWS, an American consultant of the American Bureau of Standards, is said to be the first one to use a solenoid to detect magnetic flux leakage.
After World War I and later

William Hoke, an American military major, noticed that the fine magnetic particles produced during steel parts precision grinding piled up in the wasted metal due to the process where magnetic clamps were used to hold the parts.
Later on the American Taber de FOREST makes a thorough review of the data from HOKE: his most important idea has been to use a high amperage electric current to produce the magnetic field, so far produced only through permanent magnets. He also notices that the detection of cracks in a given direction is far better if the magnetic field lines are more or less perpendicular to the cracks' plan.

Using an electric current makes it easier to match this requirement as it is sometimes possible then to choose the direction of the magnetic field lines. Further, a current flow through the part, after a Taber de FOREST's idea, produces a circular magnetisation almost impossible to get from a magnet.

1922 The American Major William E. HOKE discovers the magnetic particle crack-finding. US patent N° 1,426,384 of August 22, 1922.
He discovers that a surface or subsurface flaw in a magnetized material induces a distortion of the magnetic field that goes beyond the surface of the part. A fine ferromagnetic powder applied on the parts causes a build-up of powder on top of the flaw and formed a visible indication.
1931 Elmer A. SPERRY invents a fissure detector for steel rails based on electric current induction/magnetic field detection system. US patent N° 1,804,380 of May 5, 1931.
MT quickly replaces the oil-and-whiting method (an early way to perform liquid penetrant inspection) as the method of choice for the railroad industry to inspect steam engine boilers, wheels, axles, and tracks.
1934 Carl E. BETZ invents the tool steel ring, forerunner of the Ketos ring (Aerospace Standard AS5282).
1934 and 1935 Taber V. de FOREST applies for the first patent for particles of different dimensions and magnetic characteristics; lubricating-material and non-magnetic-coated particles. US patent N° 1,960,898 of May 29, 1934.
Between 1934 and 1938 First water-based magnetic inks.
1935 Carl E. BETZ improves the formulation, and the manufacturing of the powders and pastes used in the wet method.
1936 Glen D. BAGLET invents the (current flow technique) magnetic bench. US patent N° 2,061,692 of November 24, 1936.
1937 The German physicist Friedrich FÖRSTER (1908-1999) invents the probe for the detection of very weak modifications of magnetic fields due to cracks.
AC portable MT unit for railroad parts inspection.
From 1938 During World War II, the process is massively used in the aircraft industry.
1940 Hand-held (UV-A) lamp fitted with a separate Woods glass filter.
1941 Portable HWDC unit and powder blower.
Robert C. SWITZER invents the fluorescent detection media. US patent N° ,267,999 of December 30, 1941.
1942 Forster B. DOANE invents a means for maintaining ferromagnetic particles in suspension. US patent N° 2,301,203 of November 10, 1942.
Tool steel ring, forerunner of the Ketos ring (Aerospace Standard AS5282) is introduced in the industry.
1944 Alfred V. de FOREST invents the first permanent magnet for MT. US patent N° 2,353,550 of July 11, 1944.
1946 Grant W. COON invents the magnetic particle testing system in which parts may be tested by both current and magnetic flow techniques. US patent N° 2,394,152 of February 5, 1946.
Foster B. DOANE invents the magnetic bench fitted with a dial switch for controlling current intensity both through the coil and through the test piece. Needled ammeters. US patent N° 2,401,467 of June 4, 1946.
1947 Raymond L. FITCH invents the automatic magnetic bench. US patent N° 2,430,167 of November 1947.
From 1950 Spray cans for MT materials.
Ca 1950 Berthold penetrameter.
Pie gage (ASME).
1953 First MT unit designed in France.
1955 The English Raphael Isaac MINCHOM invents the permanent magnet fitted with legs with multiple articulations. US patent N° 2,722,636 of November 1, 1955.
1958 Taber V. de FOREST invents the permanent magnet yoke. US patent N° 2,832,922 of April 29, 1958.
1960 First French magnetic bench, output power manually set using transformers with preselected contacts. Needled ammeters.
Vers 1960 FLUXA test block.
MTU N° 3 test block, listed much later as reference block type 1 in the ISO 9934-2:2002 standard.
1964 David DIPERSTEIN invents the AC and DC hand-held electromagnet yoke fitted with fixed legs. US patent N° 3,146,396 of August 25, 1964.
1968 The American Phillip J. PARKER invents the electromagnet yoke with adjustable legs and self-contained circuitry for AC and DC testing. US patent N° 3,378,762 of April 16, 1968.
Ca 1970 Use in France of the water-based magnetic inks.
Moving-coil tangential magnetic field meter. (The Förster 1580 has been the reference in MT measurement for a long time).
1972 Swinging field technique on magnetic bench.
January 21,1975 The Americans Henry J. Weltman, Mark T. Carroll, John E. Halkias, William T. Kaarlela and Jack D. Reynolds invent the magnetic rubber for the detection of discontinuities in threads on the inside diameter of holes. US patent N° 3,862,047.
1975 Output power control of the current generator by thyristors dimmer replacing step transformers.
From October 1978 Total halogens (chlorine, fluorine, then, subsequently, bromine) content and sulphur content checked in MT materials, according to the French Electricity Board (EDF) RCC-M code.
Ca 1980 Foil-type magnetic flux strip (slotted flux strip).
Combined digital radiometer/luxmeter.
1985 Magnetic bench comprising a thyristor-controlled infinitely variable current and digital display and timers.
Ketos ring (Aerospace Standard AS5282).
1988 Michel TOITOT, a French Engineer invents the ‘‘Témoin C’’, later listed as reference block type 2 in the ISO 9934-2:2002 standard.
1990 Digital tangential magnetic field meter and analyser. These meters, such as the ADC3, are finally able to measure ‘‘TRMS’’ (True Root Mean Square) magnetic fields given by thyristor-controlled magnetic benches.
By mid ‘90 Swinging field produced through AC magnetic heads on magnetic bench.
1993 Non-contact MT technique by swinging field in 2D or 3D chamber.
1995 First AC magnetic heads in France (they have been in service for several years especially in Germany) and increased use of swinging-field benches.
Fan cooled hand-held (UV-A) lamp fitted with a separate Woods glass filter.
1996 Card with magnetic stripe for testing MT detection media.
1997 First magnetic bench comprising a computer-controlled process (better reliability and repeatability).
1998 (UV-A) sources fitted with µ-xenon discharge bulb.
1999 Magnetic bench fitted with a switchboard with ‘‘prerecorded parameters’’ and automatic programmable logic controller (PLC).
February 11, 2002 Non-contact MT technique by induced current flow.
2003 Pocket-size tangential magnetic field meter (Analysse®). Miniaturized and user-friendly meter.
2004 • Fully computerized control of MT benches.
• Friendly and easy-to-use touch screens.
• Setting and recording of readjusted parameters.
• Automatic adjustment of current flow.
From 2004 (LED) Light-emitting diode (UV-A) sources.
From 2007 (LED) Light-emitting diode (blue light) sources.
Last Updated ( Thursday, 20 November 2014 13:43 )