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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The test methods may be applied to specimens with equiaxed or elongated grain structures with either uniform or duplex grain size distributions. These methods are based on certain rules to decide which grains that intersect the test area border are fully sized or not sized at all.
Generally, each test line will begin and end within a grain and these partial chords are not measured see Table 1. A large number of measurements over several? A third approach is to transfer the microstructural image, test grid image and cursor image to a television monitor.
Prior to automatic image analysis, the grain boundaries should be thinned and the etch pitting must be removed. However, because of the problems associated with counts at the ends of the test lines, this practice is not recommended unless half intercepts or intersections can be tallied separately. A values for the? To avoid problems with adherent tissue paper, follow the alternate leveling procedure described in Practice E Procedure section.
Each micrograph should contain at least? Subjecting the specimen to a temper embrittlement cycle may enhance the etch response, but this treatment is not helpful if the amounts of P, Sn, As, and Sb are very low. Take the micrographs at random, that is, without bias in the?
Annex A1 describes methods for measuring the grain size of non-equiaxed structures and for evaluating the degree of grain shape anisotropy. There may be other methods or alternate procedures that can produce acceptable results but they must be carefully evaluated before use see The nature of the heat treatment is usually important, particularly the tempering temperature, if used.
These features should be removed from the? This measurement can be performed asym If an excessively high number of grains are present in the image, measurement precision will be impaired. Using the equation relating either P and G or?
ASTM E1382 – 97(2015)
Digital correction methods for nonuniform illumination may be used subsequently; however, these methods should not be used in lieu of proper microscope alignment and adjustment.
Asym best possible sequence of specimen preparation and etching should be used before relying upon video e132 to further improve the image prior to detection.
The measurement area, Ati, is then determined by combining the grain boundary and grain interior images, if the number of grains per unit area is to be determined. Measure entire area of the largest observed grain section.
Measure areas of whole grains only. Light pen, mouse, or trackball editing of images to complete missing grain boundaries before measurement is an acceptable technique, although slow. 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.
Hence, because these methods are based upon two different geometrical characteristics of the xstm structure, minor grain size differences may result when the planar grain size is determined using methods ast, on LV vs.
Drop the measurement grid onto the photograph to prevent placement bias. E1832 based on the average grain area or the number of grains per unit area are directly related to the total length of grain edges per unit volume, LV. These images, which usually xstm low light intensities, can be measured using a digitizing tablet but may be more difficult to measure with automatic image analyzers.
To do this, sort the intercept lengths in ascending order, separate the data into the two individual distributions, and compute? This procedure is useful for 1e382 the overall mean shape of the grains but does not give size information.
Grain contrast 1 and tint etchants 1,2 are very effective because they generally provide full delineation of the grain structure.
Image editing cannot be performed reliably. For this example, we obtain 2. The microscopist moves the cursor across the tablet surface while watching the monitor to make the appropriate measurements. Tape the grid corners to the micrograph or tablet surface to prevent movement during measurement. The etch delineation is too poor for accurate measurement. The measurement area is the sum of the grain interior and grain boundaries between these grains, Ati. The standard deviations for the measurements on each speci?
Use of a programmable stage prevents bias in? Measure only whole intercept lengths, ignore intercepts that end within a grain.
No further reproductions authorized. In practice, it is equations for P generally easier to make Wstm counts intersections of test lines with grain boundaries than N counts interceptions of test lines with grains.
Detection of these features, particularly during measurement with an automatic image analyzer, will bias test results. If the grain size varies within the product, specimen and?
High levels of humidity must be avoided as staining of specimen surfaces may occur during, or before, analysis. Discrimination of grain boundaries but not twin boundaries using image amendment techniques may be possible with some automatic image analyzers.