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 cementite grain boundary?
This determine the average grain area of the a phase, A measurement can be performed using? These devices relieve much of the tedium associated with manual measurements, thus permitting ast of a larger amount of data and more extensive sampling which will produce better statistical de?
Each micrograph should contain at least? NOTE 2—There are other procedures for dealing with grains that intersect the test area border. If the grains are equiaxed, measurements using any orientation for the chords is acceptable.
When using an eyepiece reticle, use of a single test circle, of ashm signi?
Scratches from grinding, or from polishing with abrasives larger than about 1-? These images, which usually exhibit low light intensities, can be measured using a digitizing tablet but may be more difficult to measure with automatic image analyzers. However, the presence of an equiaxed grain structure in a wrought specimen can only be determined by examination of a plane of polish parallel to the deformation axis.
If this cannot be done, count every other triple point intersection twice. Permission rights to photocopy the standard may also be secured from the ASTM website www. However, to eliminate grain anisotropy effects non-equiaxed grainseither the image should be rotated using a prism to rotate the live 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.
Individual reprints single or multiple copies of this standard may asttm obtained by contacting ASTM at the above address or at phonefaxor service astm.
Grain contrast 1 and tint etchants 1,2 are very effective because they generally provide full delineation of the grain structure. When counting grain boundary intersections, which is usually easier, a tangential intersection with a grain boundary is counted as one intersection.
This procedure should be repeated on each of at least? Similar results can be obtained using alkaline sodium picrate, boiling or electrolytically. NOTE 1—Equations 2 and 3 are for single phase grain structures.
These equations measured parameters: 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 If measurements were made on only a single plane, for example, the asrm plane, report that this was done and the nature of the test method, plus the statistical evaluation of the data.
In such cases, the grain size must be measured on the three principal awtm and averaged as described in Annex A1. Hence, because these methods are based upon awtm different geometrical e13382 of the grain structure, minor grain size differences may result when the planar grain size is determined using methods based on LV vs.
Then, make enlargements of the grain structure images using the same enlarger setting. The standard deviations for the measurements on each speci? In general, coarse-grained specimens are more easily etched for prior-austenite grain size. Calibration and Standardization Vibrations, if excessive, must qstm isolated, particularly for automatic image analysis.
Such techniques may be employed if the operator can demonstrate their reliability.
ASTM E1382 – 97(2015)
Guidelines and recommended practices are given in Practice E3. Other treatment conditions, such as as-hot rolled, as-hot astmm, 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.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of aztm limitations prior to use. If an excessively high number of grains are present in the image, measurement precision will be impaired.
Automatic image analyzers are affected by these problems to a greater degree than are semiautomatic digitizing tablet measurements. Counting accuracy will be impaired if the number of grains visible is excessively high smaller apparent size in the? L is the number of grain boundary intersections per unit length.
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.
Measure only whole intercept chord lengths, delete grains intersecting the test area border. Because of the uncertainties introduced by such procedures, they should be used with caution, or avoided, until their in?
The number of whole grains counted per micrograph is Ni. The grain boundary image can be thinned by erosion to delete any particles at the astk and then this If the histogram reveals a duplex condition, calculate s for the intercepts within each region of the distribution curve.
Annex A1 provides information concerning the measurement of grain size and grain anisotropy for non-equiaxed grain structures. Summary of Test Method. Generally, each test line will begin and end within a grain and these partial chords are not measured see Table 1. A, is determined in accordance with Eq