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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Easily measured using a digitizing tablet and by automatic image analysis after a minor amount of image editing.

ASTM E1382 – 97(2015)

L only will be presented. L data and Eq A1. Grains intersecting the test area border must be deleted. The cementite grain boundary?

Last previous edition approved in as E — 97 If the grain structure is not equiaxed but elongated, ast grain size measurements on specimens with different orientations will vary.

On each micrograph, mark off or number each grain fully within the borders of the print. E13882 general, it is difficult to reveal the prior-austenite grain boundaries to the level required for automatic image analysis, unless the image can be edited successfully prior to measurement, and measurements with a digitizing tablet may be preferable.

Alternatively, a greater number of micrographs can be made and analyzed. Annex A1 provides information concerning the measurement of grain size and grain anisotropy for non-equiaxed grain structures.

A reasonable estimate of the grain size may be obtained by measurements made on the longitudinal plane only, depending upon the manner in which the grain shape has been distorted. For this measurement, the standard deviation of the area fraction or point fraction of the a phase and the Nai values should be determined. For s1382 of the three principle test planes, three directions perpendicular to those shown in Fig.

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.

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Fix each micrograph to the tablet surface, for example using masking tape, to prevent movement during analysis. If measurements were made using only the longitudinal plane, determine the mean value of the measurements.

ASTM E()_图文_百度文库

In general, coarse-grained specimens are more easily etched for prior-austenite grain size. 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.

Automatic image analyzers are affected by these problems to a greater degree than are atm digitizing tablet measurements. Discrimination of grain boundaries but not twin boundaries using image amendment techniques may be possible with some automatic image analyzers.

E182 pooled standard deviation, spooled, is computed from the pooled variance s2 pooled for the three oriented measurements: Use of a programmable stage prevents bias in? Al ast, 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.

If the cursor can be programmed to record each triple point intersection as 11? Prior to analysis, center the light source as described in the operating instructions for the microscope and adjust the?

L is the number of grains intercepted per unit length. N can be entered into the computer program, or used with a hand calculator, to determine G.

Grain contrast 1 and tint etchants 1,2 are very effective because they generally provide full delineation of the grain structure. For example, for optically anisotropic materials that are difficult to etch, crossed polarized light may be required to observe the grain structure. Excessively deep etching with such etchants to bring out the fainter boundaries should not be done because deep etching creates excessive relief deviation from planar conditions and will bias certain measurements, particularly grain intercept lengths and grain areas, performed by automatic image analysis and also measurements made with a digitizing tablet.

To avoid problems with adherent tissue paper, follow the alternate leveling procedure described in Practice E Procedure section. The best possible sequence of specimen preparation and etching should be used before relying upon video techniques to further improve the image prior to detection. Methods 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.


A substantial percentage of the grain boundaries are not visible and the annealing twins are revealed. L P mm-1 A very high degree of grain boundary delineation is required.

This image can be inverted reverse detected and non-detected pixels to produce the grain boundaries within the measurement? The microscopist moves the cursor across the f1382 surface while watching the e382 to make the appropriate measurements. If each P to a mean lineal intercept length using Eq 5, and the mean?

L is the number of grain boundary intersections per unit length. All scratches and smearing must be removed, although very? Measure only whole intercept lengths, ignore intercepts that end within a grain. The standard deviations for the measurements asm each speci? L, or the mean grain boundary intersections per unit length, P? For such specimens, semiautomatic digitizing tablet measurements are preferred.

Precision and Bias If the test line should intersect a junction between four grains, which occurs rarely, count this intersection twice, that is, as 2 intersections.

The grains of interest are detected as described in These features must be eliminated from the image before automatic image analysis is conducted. Generally, each test line will begin and end within a grain and these partial chords are not measured see Table 1.

Round off the value of G to the? Round off the grain size number to the nearest tenth unit. There may be other possible methods, or other xstm procedures, that can be used to measure grain size.