STP430

    Use of the AMEDA Microscope in Quantitative Microscopy

    Published: Jan 1968


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    Abstract

    In March 1965, The Youngstown Sheet and Tube Co. received an AMEDA system (Automatic Microscope Electronic Data Accumulator). This system, designed and manufactured by Femco, Inc., Irwin, Pa., was the first to be used in a steel company research laboratory and was built to Youngstown's specifications, incorporating the principles of an automated point counting microscope developed by laboratory personnel of the Consolidation Coal Co.

    Basic functions of the AMEDA system are to point count microconstituents of a specimen based on differences in the amount of reflected or transmitted light emitted from an entity as it passes under a microscope objective at a constant rate of speed, and to categorize these entities into preset size categories. Logic circuitry is provided to record the output of multiple reflectance or transmission levels, particle sizes, and particle size distribution. The number and type of outputs is determined by each mode of operation. The size determinations are carried out at a traversing speed of 1 mm/sec, and the size categories are expressed in microns and set as follows: below 3, 4-7, 8-15, 16-31, 32-63, 64-127, 128-255, 256-511, 412-1023, and plus 1024; however, these categories can be altered by replacing various electronic components. Accumulation of particle sizes is done at specific reflectance levels as set on the control unit. The logic circuitry can also be set up to carry out point counting and size distribution simultaneously. The unit has been used successfully in the following areas: (1) determination of the volume fraction, average particle size, and distribution of pyrite in coal; (2) the microstructure of metallurgical coke in terms of porosity and the relative amount and size of pores and walls; (3) volume fraction, average particle size, and distribution of certain nonmetallic inclusions in steel specimens; (4) determination of the number and average size of surface pits on tin plate; (5) quantitative determination of the amount of rust developed on tin plate specimens subjected to corrosive atmospheres; and (6) determination of the average grain size and distribution in steel specimens.

    Keywords:

    metallography, microscopes, automation, microstructure, grain size, particle size, coke, coal, steels, inclusions, porosity, pitting (corrosion)


    Author Information:

    Bayer, J. L.
    Former senior research engineer, research supervisor, and research engineer, The Youngstown Sheet and Tube Co., Youngstown, Ohio

    Denton, G. H.
    Former senior research engineer, research supervisor, and research engineer, The Youngstown Sheet and Tube Co., Youngstown, Ohio

    Hassel, R. E.
    Former senior research engineer, research supervisor, and research engineer, The Youngstown Sheet and Tube Co., Youngstown, Ohio


    Paper ID: STP41816S

    Committee/Subcommittee: E04.03

    DOI: 10.1520/STP41816S


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