ASTM E() – Standard Test Methods for Determining Average Grain Size Using Semiautomati. Purchase your copy of ASTM E – 97() as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards. The ASTM Designation: E–97 requires five hundred data points for a given sample and this analysis is time-consuming and tedious for the.
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Round off the value of G to the? ALA grain size; anisotropy index; area fraction; ASTM grain size number; austenite grains; automatic image analysis; calibration; chord length; confidence level; digitizing tablet; duplex grain structures; equiaxed grains; etchant; ferrite grains; grain boundary; grains; grain size; intercept length; intersection count; magnification; non-equiaxed grains; polycrystalline; prior-austenite grain boundaries; relative accuracy; semiautomatic image analysis; skeletonization; standard deviation; twin boundary; watershed segmentation.
Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. L value is converted grain size was found to be The boundaries are reasonably well developed and the specimen can be analyzed with a digitizing tablet but some editing would be required for automatic image analysis.
When working with a new alloy composition or a new etchant, it may be helpful to measure the grain size as a function of etch time, or other experimental conditions, to develop a reliable practice 10 that agrees with manual determination of the grain size in accordance with Test Methods E The simplest is to?
Next, divide Li by the true? The operator should evaluate the precision and accuracy of such methods on specimens carefully evaluated by one or more of the recommended methods before utilizing an alternate method or procedure.
A substantial percentage of the grain boundaries are not visible and the annealing twins are revealed. When using a live microscope image and an eyepiece reticle, simply select more? The etch delineation is too poor for accurate measurement. However, as with manual application of the Jeffries method, the tablet method also requires marking off of the grains in order to obtain an accurate count. If directed test lines were used on one, two or three planes, determine the mean of the measurements and any desired anisotropy ratios.
Use of a programmable stage prevents bias in? Unmounted specimens generally should have a surface area much larger than required for measurement to facilitate leveling, if automatic image analysis is to be utilized, as described in Measure the entire area of the largest observed grain section.
These devices relieve much of the tedium associated with manual measurements, thus permitting collection of a larger amount of data and more extensive sampling which will produce better statistical de?
Calibration and Standardization For this measurement, the standard deviation of the area fraction or point fraction of the a phase and the Nai values should be determined.
Note that of the three principle planes, that is, A? To do this, sort the intercept lengths in ascending order, separate the data into the two individual distributions, and compute? L for a single phase grain structure. Calculate the grain size number based on the mean of the measurements using Table 2 or the equations in Table 3. There may ee1382 other possible methods, or other equivalent procedures, that can be used to measure grain size.
Detect the grain interiors in the manner described in This procedure is useful for e11382 the overall mean shape of the grains but does ashm give size information. Enlargements are easiest to use.
However, if the grains exhibit anisotropy, that is, they are not equiaxed, the image must be either rotated using a prism to rotate the live video image, or the digitized image can be rotated in memory, or scan lines of several orientations may be used, depending upon the capabilities of the image analyzer used. For automatic image analysis, the computer also controls all of the operations except, perhaps, focusing automatic focusing is optional.
For accurate measurement of intercept lengths or grain areas, the smallest grains should be at least 5 mm in diameter on the television monitor 9 for a typical — mm 12—13 in.
If the grains are w1382, measurements using any orientation for the chords is acceptable. Moderate image editing is required. L values are handled in the same way as P mens. Other treatment conditions, such as as-hot rolled, as-hot forged, or as-cold drawn, may be tested as required but it must be recognized that the grain structure for these conditions may not be equiaxed.
A very high degree of grain boundary delineation is required. The easiest method is the measurement of intercept lengths of straight test lines in the phase of interest, as described in paragraph These values could be written in the form? The cementite grain boundary? Such a computation is easy to perform if the data can be read asrm a spreadsheet type computer program.
Prices subject to change without notice. Current edition approved Nov. If a digitizing tablet is utilized for the measurements, illumination modes other than bright?
With an upright-type microscope, place the specimen on a slide and level the surface using clay or plasticene between the specimen and slide. Grain boundary delineation is inadequate for automatic image analysis without extensive editing. R1382 the cursor can be programmed to record each triple point intersection as 11?
All scratches and smearing must be removed, although very? Afor n measured?
ASTM E1382 – 97(2015)
Automatic Image Analysis Measure only whole intercept awtm lengths, delete grains intersecting the test area border. The average number of intercepts or intersections should be aboutwith a minimum of 70 and a maximum of unless the grain size is too coarse.
The microscopist moves the cursor across the tablet surface while watching the monitor to make the appropriate measurements. These methods are based on certain rules to decide which grains that intersect the axtm area border are fully sized or not sized at all.