ET01.pdf

The electromagnetic test method includes several

This preview shows page 13 - 14 out of 25 pages.

The electromagnetic test method includes several subsidiary methods, sometimes called submethods or techniques: eddy current testing, remote field testing, flux leakage testing, alternating current field measurement testing and microwave testing. Of these several submethods, conventional eddy current testing is the most widely used. Magnetic particle testing is an electromagnetic test that industry administers as a separate method. Applications of eddy current tests in industry are numerous and widespread. The total number of test measurements made annually by this nondestructive test method may exceed that of all other methods combined. Eddy current testing is used for the following: 1. noncontacting measurement of the thickness of metallic foils, sheets, plates, tube walls and machined parts from one side only; 2. measurement of the thickness of coatings over base materials where the coating and base material have significantly different electrical or magnetic properties; 3. identifying or separating materials by composition or structure; 4. detecting material discontinuities that lie in planes transverse to the eddy currents, such as cracks, seams, laps, score marks or plug cuts, drilled and other holes and laminations at cut edges of sheet or plate; 5. identifying and controlling heat treatment conditions and evaluation of fire damage to metallic structures; 6. determining depths of case hardening of steels and some ferrous alloys; 7. locating hidden metallic objects such as underground pipes, buried bombs or ore bodies, or metallic objects accidentally packaged in foodstuffs; 8. timing or locating the motions of hidden parts of mechanisms, counting metallic objects on conveyor lines or detecting metallic missiles in flight; and 9. precise dimensional measurement of symmetric, machined or ground and polished metallic parts, such as bearings and bearing races, small mechanism components and others. Advantages of Electromagnetic Testing Modern eddy current and electromagnetic test techniques offer low cost means for high speed, large scale testing of metallic materials such as those used in nuclear, aerospace, marine, high pressure, high temperature and high speed engineering systems where premature failures could represent economic disasters or the endangering of human life. The method’s special suitability for testing of automobiles, engines, machine parts and consumer products has long been recognized. Like other nondestructive methods, eddy current tests permit measurements of material properties and dimensions and detection of discontinuities. In general, electromagnetic tests provide nearly instantaneous measurements. The test speed and modern signal analysis permit such analysis to be performed in real time. Consequently, the method can be used in production lines to test swiftly moving bars, tubes, sheets, plates, welds and other symmetric parts. These parts either pass through test coils or are scanned by moving test probes. The automation of eddy current testing and
Image of page 13

Subscribe to view the full document.

Image of page 14
  • Fall '19
  • The Land, Nondestructive testing, electromagnetic testing

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern