GB1498218A - Method and apparatus for detecting the presence of magnetic anomalies in ferromagnetic and non-ferromagnetic materials - Google Patents

Method and apparatus for detecting the presence of magnetic anomalies in ferromagnetic and non-ferromagnetic materials

Info

Publication number
GB1498218A
GB1498218A GB23123/75A GB2312375A GB1498218A GB 1498218 A GB1498218 A GB 1498218A GB 23123/75 A GB23123/75 A GB 23123/75A GB 2312375 A GB2312375 A GB 2312375A GB 1498218 A GB1498218 A GB 1498218A
Authority
GB
United Kingdom
Prior art keywords
output
velocity
amplifier
magnetic
tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB23123/75A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kennecott Corp
Original Assignee
Kennecott Copper Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kennecott Copper Corp filed Critical Kennecott Copper Corp
Publication of GB1498218A publication Critical patent/GB1498218A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • G01N27/9046—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents by analysing electrical signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

1498218 Magnetic flaw detectors KENNECOTT COPPER CORP 27 May 1976 [17 June 1974] 23123/75 Heading GIN In an arrangment for detecting the presence of magnetic anomolies in ferromagnetic and non- ferromagnetic materials the output is modified to take account fo the velocity of passage of the material being tested through the detector head. A rod, wire, tube or bar 6 of material to be tested is driven by a pair of rollers 15 through a guide tube 5 extending axially through a cylindrical magnet 10 producing in tube 5 substantially uniform magnetic field. A pair of closely coupled series connected sensing coils 4, 14 are positioned around tube 5 and coupled in phase opposition by transformer 15 to amplifier 8; alternatively the coils may be wound in series opposition in which case a normal step-up transformer may be used. The e.m.f. induced in the coils 4, 14 by the passage of the material 6 therethrough will be proportional in amplitude to the magnitude of magnetic dipoles included in the anomolies and to their velocity through the field of the magnet 10. In order to make the output of amplifier 8 independent of the velocity the tachometer 12 is positioned as shown and its output is applied to one input of operational amplifier 10, the output of which is connected to a photo-conductive cell 12 which modifies the feedback impedance across amplifier 8 so that the gain of the latter varies inversely with the velocity of tube 6. Thus the output of 8, which may be fed to a CRT or strip chart recorder 9, is proportional to the size of the anomoly, external field disturbances cancelling out. Magnet 10 is made to have a sufficiently long magnetic field so that the dipoles can charge to a uniform degree independent of the magnetic constant of the ferromagnetic material and any eddy currents in the tube 6 as a result of magnetic discontinuities at the entrance of the magnet 10 have time to decay before the part passes through the coils. In an alternative circuit for providing velocity compensation Fig. 4 (not shown) the amplifier 8 has a linear gain characteristic and its output is coupled via a diode to the indicator, the diode being back biased by the output voltage from the tachogenerator. The effect of the circuit is to increase the clipping of the output of the amplifier as the velocity of the speciment 6 increases.
GB23123/75A 1974-06-17 1975-05-27 Method and apparatus for detecting the presence of magnetic anomalies in ferromagnetic and non-ferromagnetic materials Expired GB1498218A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US48012774A 1974-06-17 1974-06-17

Publications (1)

Publication Number Publication Date
GB1498218A true GB1498218A (en) 1978-01-18

Family

ID=23906771

Family Applications (1)

Application Number Title Priority Date Filing Date
GB23123/75A Expired GB1498218A (en) 1974-06-17 1975-05-27 Method and apparatus for detecting the presence of magnetic anomalies in ferromagnetic and non-ferromagnetic materials

Country Status (6)

Country Link
JP (1) JPS5114091A (en)
BE (1) BE830330A (en)
DE (1) DE2526978A1 (en)
FR (1) FR2274917A1 (en)
GB (1) GB1498218A (en)
SE (1) SE408732B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4503393A (en) * 1981-10-05 1985-03-05 Exxon Production Research Co. Method and apparatus for detecting flaws in the threaded end of an elongate member using electromagnetic excitation and an automated scanning sensor
US4510447A (en) * 1981-10-26 1985-04-09 Exxon Production Research Co. Inspection apparatus for electromagnetically detecting flaws in the wall of a pipe
US4641093A (en) * 1981-07-28 1987-02-03 Institut Prikladnoi Fiziki Akademii Nauk Belorusskoi Ssr Method and device for magnetic testing of moving elongated ferromagnetic test piece for mechanical properties by utilizing the magnitude of remanent magnetic flux and a pulsed magnetic field
US6057684A (en) * 1995-10-31 2000-05-02 Yoshihiro Murakami Magnetic flaw detection apparatus using an E-shaped magnetic sensor and high-pass filter
CN110006992A (en) * 2019-03-28 2019-07-12 仓信无损检测设备苏州有限公司 Through mode eddy current sensor and detection method

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2746618C2 (en) * 1977-10-15 1986-01-30 Institut Dr. Friedrich Förster Prüfgerätebau GmbH & Co KG, 7410 Reutlingen Process and device for testing elongated metallic test material for defects
CA1208291A (en) * 1981-05-11 1986-07-22 Thomas R. Schmidt Method and apparatus for detecting flaws in tubular metallic members
DE3152920A1 (en) * 1981-07-28 1983-07-07 Inst Prikladnoj Fiz Akademii N METHOD AND DEVICE FOR ELECTROMAGNETICALLY TESTING THE MECHANICAL PROPERTIES OF A MOVABLE FERROMAGNETIC OBJECT
SE456864B (en) * 1986-08-27 1988-11-07 Toernbloms Kvalitetskontroll DEVICE FOR DETECTING AND SUPPRESSING THE IMPACT OF INTERNATIONAL MAGNETIC FIELD DURING THE VERTICAL FLOW TEST OF OMAGNETIC PROVOBJECTS
ES2367295B1 (en) * 2010-02-03 2012-09-04 La Farga Lacambra, S.A.U METHOD AND SYSTEM FOR DETECTION OF PHERROMAGNETIC PARTICLES EMBEDDED IN NON-PHERROMAGNETIC MATERIALS BY VARIATION OF THE MAGNETIC FIELD.
CN103901099B (en) * 2014-04-29 2016-06-15 国电科学技术研究院 Ferromagnetism seamless steel tube for boiler eddy current automatic detection device and method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3714558A (en) * 1970-09-02 1973-01-30 Anglo Amer Corp South Africa Magnetic sensor for detecting breaks in a steel rope including multiplier for eliminating noise

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641093A (en) * 1981-07-28 1987-02-03 Institut Prikladnoi Fiziki Akademii Nauk Belorusskoi Ssr Method and device for magnetic testing of moving elongated ferromagnetic test piece for mechanical properties by utilizing the magnitude of remanent magnetic flux and a pulsed magnetic field
US4503393A (en) * 1981-10-05 1985-03-05 Exxon Production Research Co. Method and apparatus for detecting flaws in the threaded end of an elongate member using electromagnetic excitation and an automated scanning sensor
US4510447A (en) * 1981-10-26 1985-04-09 Exxon Production Research Co. Inspection apparatus for electromagnetically detecting flaws in the wall of a pipe
US6057684A (en) * 1995-10-31 2000-05-02 Yoshihiro Murakami Magnetic flaw detection apparatus using an E-shaped magnetic sensor and high-pass filter
CN110006992A (en) * 2019-03-28 2019-07-12 仓信无损检测设备苏州有限公司 Through mode eddy current sensor and detection method

Also Published As

Publication number Publication date
DE2526978A1 (en) 1976-01-02
SE408732B (en) 1979-07-02
FR2274917A1 (en) 1976-01-09
BE830330A (en) 1975-12-17
SE7506881L (en) 1975-12-18
FR2274917B1 (en) 1978-12-08
JPS5114091A (en) 1976-02-04

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee