Astm e112-12 pdf free download

The widely cited ASTM E not only covers the measurement of average grain size by the comparison procedures as noted abovebut also the planimetric or Jeffries procedure and the intercept procedures. Utilization of semi-automatic digitizing tablets or automatic image analyzers to measure grain size is described in Test Methods E These charts were constructed to reflect the typical log-normal distribution of grain sizes that result when a plane is passed through a three-dimensional array of grains.

Please first log in with a verified email before subscribing to alerts. Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards. Historical Version s — view previous versions of standard. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. For determining the mean grain size, and the distribution of grain intercept lengths or grain areas, for polycrystalline metals and nonmetallic materials with equiaxed or deformed grain shapes, with uniform or duplex grain size distributions, and for single phase or multiphase grain structures, use the companion standard ASTM E These distributions are approximately log normal.

Need more than one copy? For higher degrees of accuracy in determining average grain size, the intercept or planimetric procedures may be used. Your email address will not be published. Asgm first verify your astmm before subscribing to alerts. Heyn Linear Intercept Procedure. Read more about subscriptions. In order to post comments, please make sure JavaScript and Cookies are enabled, and reload the page. Fracture Grain Size Method. Characterization of grain size in specimens with duplex grain size distributions is described in Test Methods E Subscription pricing is determined by: The three basic procedures for grain size estimation are: It is the responsibility of the user atsm this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

As the voice of the U. For more information, contact us by phonefax or email info document-center. These test methods do not cover 1. It is the Characterization of grain size in specimens with duplex grain responsibility of the user of this standard to establish appro- size distributions is described in Test Methods E Mea- priate safety and health practices and determine the applica- surement of individual, very coarse grains in a fine grained bility of regulatory limitations prior to use.

Terminology 3 Significance and Use 4 Determination of spatial grain size, that is, measurement of the Generalities of Application 5 size of the three-dimensional grains in the specimen volume, is Sampling 6 beyond the scope of these test methods. General Intercept Procedures 12 Current edition approved Nov. Published January Originally Heyn Linear Intercept Procedure 13 approved in Last previous edition approved as E — Hilliard Single-Circle Procedure No further reproductions authorized.

Report 18 3. X1 Referenced Adjuncts Appendix 3. Referenced Documents microstructure. In materials contain- phase constituent microstructure. The precision of circle. Results are free of bias and line. An accurate count does require marking off of the grains non-equiaxed grain structure.

A preci- unit length of test line. Results are free of bias; non-equiaxed grain structure. Because an accurate count can be made without need of non-equiaxed grain structure. For higher degrees of accuracy in determining roscopically determined grain sizes. Significance and Use based on the standard comparison charts. These charts were 4.

The test three-dimensional array of grains. Because they show a distri- methods may also be used for any structures having appear- bution of grain dimensions, ranging from very small to very ances similar to those of the metallic structures shown in the large, depending on the relationship of the planar section and comparison charts.

The three basic procedures for grain size the three-dimensional array of grains, the charts are not estimation are: applicable to measurement of individual grains. Generalities of Application intersections but, as the name suggests, involves comparison of 5. A metal structure is an aggregate of three- reticle.

There appears to be a general bias in that comparison dimensional crystals of varying sizes and shapes. Clearly, no two fields of magnification. In most cases, except for thin sheet or wire observation can be exactly the same. No nominally random process of 7. The specimen shall be ing measurements in part of a specimen. Representative etched using a reagent, such as listed in Practice E, to implies that all parts of the specimen contribute to the result, delineate most, or all, of the grain boundaries see also Annex not, as sometimes has been presumed, that fields of average A3.

Visual selection of fields, or casting out of extreme measurements, may not falsify the average when TABLE 1 Suggested Comparison Charts for Metallic Materials done by unbiased experts, but will in all cases give a false NOTE 1—These suggestions are based upon the customary practices in impression of high precision. For representative sampling, the industry. For specimens prepared according to special techniques, the area of the specimen is mentally divided into several equal appropriate comparison standards should be selected on a structural- coherent sub-areas and stage positions prespecified, which are appearance basis in accordance with 8.

No touch-up of the position so selected is Iron and steel: allowable. Only measurements made on fields chosen in this Austenitic II or IV X way can be validated with respect to precision and bias. Sampling location and 8.

Calibration frequency should be based upon agreements between the 8. Test Specimens 9. Preparation of Photomicrographs 7. However, the presence of 9. Comparison Procedure 7. If the grain structure is not equiaxed, but In this case, the grain size as well as by interlaboratory tests have shown that unless the should be evaluated on at least two of the three principle appearance of the standard reasonably well approaches that of planes, transverse, longitudinal, and planar or radial and the sample, errors may occur.

To minimize such errors, the transverse for round bar and averaged as described in Section comparison charts are presented in four categories as follows:3 16 to obtain the mean grain size.

If directed test lines are used, A combination of all four plates is also available. Grain FIG. Size No. Includes grain size numbers, 1, 2, 3, 4, 5, 6, 7, 8, at X. Includes nominal grain diameters of 0. Includes grain size numbers 1, 2, 3, 4, 5, 6, 7, 8, at X. For example, for twinned copper and brass with a contrast etch, use Plate III.

Accomplish this by comparing a projected image or a photomicrograph of a representative field of the test specimen with the photomicro- graphs of the appropriate standard grain-size series, or with suitable reproductions or transparencies of them, and select the photomicrograph which most nearly matches the image of the FIG. Report this Grain Size 0. It is not sufficient to two standard chart pictures. Grain Size No. It may be noted that alternative magnifications number is four numbers higher than that of the corresponding photomi- are usually simple multiples of the basic magnifications.

When the specimen grain size falls at either end of the Since the photographs of the standard grain size series peated checks on the same specimen using the comparison were made at 75 and diameters magnification, grain sizes method that they will be prejudiced by their first estimate. This estimated in this way do not fall in the standard ASTM disadvantage can be overcome, when necessary, by changes in grain-size series and hence, preferably, should be expressed either as diameter of the average grain or as one of the macro-grain size numbers listed in Table 3.

For the smaller macroscopic grain sizes, it may be preferable to use a higher 4 Transparencies of the various grain sizes in Plate I are available from ASTM magnification and the correction factor given in Note 3, Headquarters.

Transparencies of individual grain size groupings are available on request. This coincidence makes the fracture grain sizes interchangeable with the auste- The sizes ob- where QM is a correction factor that is added to the apparent grain size served microscopically shall be considered the primary of the specimen, when viewed at the magnification M, instead of at 1X, to yield the true ASTM macro-grain size number.

Thus, for a magnifi- standard, since they can be determined with measuring instru- cation of 2X, the true ASTM macro-grain size number is two numbers ments.

Select a magnification which grains have been revealed by any other means see Annex A3, will give at least 50 grains in the field to be counted. When the A3. Make the grain-size measurement by comparing the image is focused properly, count the number of grains within microscopic image, at magnification of X, with the stan- this area. The sum of all the grains included completely within dard grain size chart in Plate IV, for grains developed in a the known area plus one half the number of grains intersected McQuaid-Ehn test see Annex A3 ; for the measurement of by the circumference of the area gives the number of equiva- austenite grains developed by other means see Annex A3 , lent whole grains, measured at the magnification used, within measure by comparing the microscopic image with the plate the area.

Count a minimum of three fields to The Headquarters. These four corner This grain diameter has no grains together equal one grain within the test box. NInside, the grains completely within the box, and of NIntercepted, The precision of the planimetric method is a function of the where M is the magnification, A is the test figure area in mm2 number of grains counted see Section It is recom- as counting becomes tedious and inaccurate.

Because of the need to mark off the grains to obtain Do not attempt to choose fields that appear to be typical. Choose the fields blindly and select them from General Intercept Procedures different locations on the plane of polish.

These procedures are amenable to grain size of No. For areas other than the standard circle, mended that at least a manual tally counter be used with all determine the actual number of grains per square millimetre, intercept procedures in order to prevent normal errors in NA , and find the nearest size from Table 4.

The ASTM grain counting and to eliminate bias which may occur when counts size number, G, can be calculated from NA number of grains appear to be running higher or lower than anticipated. For grains intersecting the test circle are within the circle while half anisotropic structures, procedures are available either to make are outside the circle.

This assumption is valid for a straight separate size estimates in each of the three principal directions, line through a grain structure, but not necessarily for a curved or to rationally estimate the average size, as may be appropri- line. The bias created by this assumption increases as the ate. If the number of grains within the test circle is at least 50, the bias is about The relationship or rectangulat test area.

However, the counting procedure must be modified slightly. When counting intercepts, segments at uniform equiaxed grains see A2. Consequently, the rela- the end of a test line which penetrate into a grain are scored as tionship between the ASTM grain size number G and the mean half intercepts.

A tangential intersection with a view at X magnification for the microscopically determined grain boundary should be scored as one intersection. An grain size scale. The two additional intersections are to be counted.

The form of such mm on a field at X for the microscopically determined arrays is not critical, provided that all portions of the field are grain size numbers. Using this scale, measured grain size measured with approximately equal weight.

An array of lines numbers are within about 0. The determined by the planimetric method, that is, well within the number of intercepts is to be counted for the entire array and precision of the test methods. The grain boundary surface area-to- men. These relations are independent of grain Either of the mm lines of Fig. Please first verify your email before subscribing to alerts. For higher degrees of accuracy in determining average grain size, the intercept or planimetric procedures may be used.

This ensures that you are always up-to-date and saves you both time and asmt. NOK 1 ,00 excl. Characterization of grain size in specimens with duplex grain size distributions is described in Test Methods E Proceed to Checkout Continue Shopping. The three basic procedures for grain size estimation are:. These test methods do not cover methods to characterize the nature of these distributions. Measurement of individual, very axtm grains in a fine grained matrix is described in Test Methods E.

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