ASTM E1382 PDF
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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If measurements were made using only the longitudinal plane, determine the mean value of the measurements. Anisotropy indexes for the two perpendicular test orientations on the transverse and planar surfaces revealed zstm of 0. In general, coarse-grained specimens are more easily etched aatm prior-austenite grain size. Discrimination of grain boundaries but not twin boundaries using image amendment techniques may be possible with some automatic image analyzers. These features must be eliminated from the image before automatic image analysis is conducted.
For automatic image analysis, a?
This specimen can be easily measured with a digitizing tablet but substantial image editing would be required for automatic image analysis. For accurate measurement of grain intercept chord lengths or grain areas, the smallest grains should be at least 5-mm in diameter on the television monitor see e13382 In practice, it is equations for P generally easier to make P counts intersections of test lines with grain boundaries than N counts interceptions of test lines with grains.
If directed test lines are used for the analysis, measurements in the three principle directions can be made using only two of the three principle test planes. For automatic image analysis, the computer also controls all of the operations except, perhaps, focusing automatic focusing is optional.
Such images exhibit grain contrast or color differences between grains rather than grain boundary delineation. Hence, because these methods are based awtm two different geometrical characteristics of the grain structure, minor grain size differences may result when the planar grain size is determined using methods based on LV vs.
ASTM E1382 – 97(2015)
Because of the need to mark off the grains as they are counted, this method is best utilized with photomicrographs. Also, minor deviations from equiaxed conditions may accentuate these differences.
Aand by surface using the planimetric method to determine N? Light pen, mouse, or trackball editing of images to complete missing grain boundaries before measurement is an acceptable technique, although slow. These methods are based on certain rules to decide which grains that intersect the test area border are fully sized or not sized satm all. Etching techniques and e1328 that do not delineate twin boundaries are preferred for these specimens. Some grain boundaries are missing.
Note that of the three principle planes, that is, A? Specimens must be carefully cleaned and dried after polishing. The following bibliographic material is provided to assist you with your purchasing decision: Consequently, preparation of longitudinally oriented specimens, where the plane-of-polish is parallel to the deformation axis or grain elongation direction, is recommended.
However, the presence of an equiaxed grain structure in a wrought specimen can only be e1328 by examination astj a plane of polish parallel to the deformation axis. A number in parentheses indicates the year of last reapproval.
L, or the mean grain boundary intersections per unit length, P? 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. These measurements are made for a large number of grains, or all of the grains in a given area, within a microscopical?
These equations measured parameters: Round off the grain size number to the nearest tenth unit. If the histogram reveals a duplex condition, calculate s for the intercepts within each region of the distribution curve. A is the number of grains per unit area.
However, these techniques must be used with caution because skeletonization can produce false grain boundaries e13382 watershed segmentation may not produce grain boundaries between two adjacent grains with similar color or gray zstm. Methods based on the mean intercept length or the number of grain boundary intersections per unit length are directly related to the grain boundary surface area per unit volume, SV.
Grain boundary delineation is inadequate for automatic image analysis without extensive editing. The grain structure is nearly completely revealed without the twin boundaries. Excessively deep scratches, excessive relief, preparation-induced deformation, pull-out and other artifacts will produce false detail and promote inaccurate measurements.
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 astj rotated in memory, or scan lines of several orientations may be used, depending upon the capabilities of the image ashm used. Grain contrast 1 and tint etchants 1,2 are very effective because they generally provide full delineation of the grain structure.
Al or A non-equiaxed specimen can be made from N from grain count or grain area measurements on the longitudinal plane alone, or the plane parallel to the grain elongation axis. When using a live microscope image and an eyepiece reticle, simply select more? All scratches and smearing must be removed, although aetm
For this measurement, the standard deviation of the area fraction or point fraction of the a phase and the Nai values should be determined. Scratches from grinding, or from polishing with abrasives larger than about 1-?
The grain boundaries are reasonably well delineated. For such specimens, semiautomatic digitizing tablet measurements are preferred. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. 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 mean lineal intercept length,?