JPS57108656A - Detecting method of internal defect in thin steel plate - Google Patents

Detecting method of internal defect in thin steel plate

Info

Publication number
JPS57108656A
JPS57108656A JP18412380A JP18412380A JPS57108656A JP S57108656 A JPS57108656 A JP S57108656A JP 18412380 A JP18412380 A JP 18412380A JP 18412380 A JP18412380 A JP 18412380A JP S57108656 A JPS57108656 A JP S57108656A
Authority
JP
Japan
Prior art keywords
steel plate
thin steel
magnetic flux
leaked magnetic
detecting
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.)
Pending
Application number
JP18412380A
Other languages
Japanese (ja)
Inventor
Hiroyuki Morita
Kazuhiro Hirata
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.)
JFE Steel Corp
Original Assignee
Kawasaki Steel 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 Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Priority to JP18412380A priority Critical patent/JPS57108656A/en
Publication of JPS57108656A publication Critical patent/JPS57108656A/en
Pending 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
    • G01N27/83—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws by investigating stray magnetic fields

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)

Abstract

PURPOSE:To make it possible to judge the internal defetcts in the thin steel plate accurately by generating magentic flux in the thin steel plate by a magnet, detecting the leaked magnetic flux by detecting elements provided as the separate bodies on top and bottom sides, and utilizing the sum and difference of both detected signals. CONSTITUTION:The DC electromagnetic B is placed on the top surface of the thin steel plate C and the magnetic flux E is generated. The leaked magnetic flux G is detected by the detecting element D on the top surface, and the leaked magnetic flux G' is detected by the detecting element D' on the back surface. The relationship between the leaked magnetic fluxes G and G' and the de- tected signals X and Y after the amplification in amplifiers H and H' in the detecting elements D and D' is such that the signals X and Y linearly extend in a symmetic pattern, with the leaked magnetic flux (a) as the ordinate and the thickness of the thin steel plate (b) as the abscissa. The magnitude of the defect can be judged by the signal of X+Y. By normalizing with the value of X+Y, the position can be judged by using the signal of X-Y as a depth signal.
JP18412380A 1980-12-26 1980-12-26 Detecting method of internal defect in thin steel plate Pending JPS57108656A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP18412380A JPS57108656A (en) 1980-12-26 1980-12-26 Detecting method of internal defect in thin steel plate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP18412380A JPS57108656A (en) 1980-12-26 1980-12-26 Detecting method of internal defect in thin steel plate

Publications (1)

Publication Number Publication Date
JPS57108656A true JPS57108656A (en) 1982-07-06

Family

ID=16147771

Family Applications (1)

Application Number Title Priority Date Filing Date
JP18412380A Pending JPS57108656A (en) 1980-12-26 1980-12-26 Detecting method of internal defect in thin steel plate

Country Status (1)

Country Link
JP (1) JPS57108656A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2678384A1 (en) * 1991-06-26 1992-12-31 Centre Techn Ind Mecanique Electromagnetic device for detecting faults in a cable
JPH0572181A (en) * 1991-09-13 1993-03-23 Nkk Corp Magnetic-field inspection device
JPH05196581A (en) * 1992-01-20 1993-08-06 Nkk Corp Measurement device for defect harmfulness of steel plate
US5235275A (en) * 1990-02-22 1993-08-10 Nkk Corporation Magnetic inspection apparatus for thin steel strip having magnetizer and detection coil within a hollow roller rotated by the steel strip
US6479992B2 (en) 2000-07-12 2002-11-12 Nkk Corporation Leakage flux flaw detecting method and method for manufacturing hot rolled steel sheet using the same
JP2003025017A (en) * 2001-07-11 2003-01-28 Nkk Corp Hot-rolled steel sheet to which information of flaw detection result is appended and its manufacturing method
EP3851846A1 (en) * 2011-12-15 2021-07-21 Posco Defect inspection device for steel plate

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5235275A (en) * 1990-02-22 1993-08-10 Nkk Corporation Magnetic inspection apparatus for thin steel strip having magnetizer and detection coil within a hollow roller rotated by the steel strip
FR2678384A1 (en) * 1991-06-26 1992-12-31 Centre Techn Ind Mecanique Electromagnetic device for detecting faults in a cable
JPH0572181A (en) * 1991-09-13 1993-03-23 Nkk Corp Magnetic-field inspection device
JPH05196581A (en) * 1992-01-20 1993-08-06 Nkk Corp Measurement device for defect harmfulness of steel plate
US6479992B2 (en) 2000-07-12 2002-11-12 Nkk Corporation Leakage flux flaw detecting method and method for manufacturing hot rolled steel sheet using the same
JP2003025017A (en) * 2001-07-11 2003-01-28 Nkk Corp Hot-rolled steel sheet to which information of flaw detection result is appended and its manufacturing method
JP4724967B2 (en) * 2001-07-11 2011-07-13 Ｊｆｅスチール株式会社 Manufacturing method of hot-rolled steel sheet with information on flaw detection results
EP3851846A1 (en) * 2011-12-15 2021-07-21 Posco Defect inspection device for steel plate

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