ASTM E112-12
(Test Method)Standard Test Methods for Determining Average Grain Size
Standard Test Methods for Determining Average Grain Size
SIGNIFICANCE AND USE
4.1 These test methods cover procedures for estimating and rules for expressing the average grain size of all metals consisting entirely, or principally, of a single phase. The test methods may also be used for any structures having appearances similar to those of the metallic structures shown in the comparison charts. The three basic procedures for grain size estimation are:
4.1.1 Comparison Procedure—The comparison procedure does not require counting of either grains, intercepts, or intersections but, as the name suggests, involves comparison of the grain structure to a series of graded images, either in the form of a wall chart, clear plastic overlays, or an eyepiece reticle. There appears to be a general bias in that comparison grain size ratings claim that the grain size is somewhat coarser (1/2 to 1 G number lower) than it actually is (see X1.3.5). Repeatability and reproducibility of comparison chart ratings are generally ±1 grain size number.
4.1.2 Planimetric Procedure—The planimetric method involves an actual count of the number of grains within a known area. The number of grains per unit area, NA , is used to determine the ASTM grain size number, G. The precision of the method is a function of the number of grains counted. A precision of ±0.25 grain size units can be attained with a reasonable amount of effort. Results are free of bias and repeatability and reproducibility are less than ±0.5 grain size units. An accurate count does require marking off of the grains as they are counted.
4.1.3 Intercept Procedure—The intercept method involves an actual count of the number of grains intercepted by a test line or the number of grain boundary intersections with a test line, per unit length of test line, used to calculate the mean lineal intercept length, ℓ. ℓ is used to determine the ASTM grain size number, G. The precision of the method is a function of the number of intercepts or intersections counted. A precision of better than ±0.25 grain size uni...
SCOPE
1.1 These test methods cover the measurement of average grain size and include the comparison procedure, the planimetric (or Jeffries) procedure, and the intercept procedures. These test methods may also be applied to nonmetallic materials with structures having appearances similar to those of the metallic structures shown in the comparison charts. These test methods apply chiefly to single phase grain structures but they can be applied to determine the average size of a particular type of grain structure in a multiphase or multiconstituent specimen.
1.2 These test methods are used to determine the average grain size of specimens with a unimodal distribution of grain areas, diameters, or intercept lengths. These distributions are approximately log normal. These test methods do not cover methods to characterize the nature of these distributions. Characterization of grain size in specimens with duplex grain size distributions is described in Test Methods E1181. Measurement of individual, very coarse grains in a fine grained matrix is described in Test Methods E930.
1.3 These test methods deal only with determination of planar grain size, that is, characterization of the two-dimensional grain sections revealed by the sectioning plane. Determination of spatial grain size, that is, measurement of the size of the three-dimensional grains in the specimen volume, is beyond the scope of these test methods.
1.4 These test methods describe techniques performed manually using either a standard series of graded chart images for the comparison method or simple templates for the manual counting methods. Utilization of semi-automatic digitizing tablets or automatic image analyzers to measure grain size is described in Test Methods E1382.
1.5 These test methods deal only with the recommended test methods and nothing in them should be construed as defining or establishing limits of acceptability or fitness of purpose of the m...
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Designation: E112 − 12
StandardTest Methods for
1
Determining Average Grain Size
This standard is issued under the fixed designation E112; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
INTRODUCTION
These test methods of determination of average grain size in metallic materials are primarily
measuring procedures and, because of their purely geometric basis, are independent of the metal or
alloy concerned. In fact, the basic procedures may also be used for the estimation of average grain,
crystal, or cell size in nonmetallic materials. The comparison method may be used if the structure of
the material approaches the appearance of one of the standard comparison charts. The intercept and
planimetric methods are always applicable for determining average grain size. However, the
comparison charts cannot be used for measurement of individual grains.
1. Scope 1.4 These test methods describe techniques performed
manually using either a standard series of graded chart images
1.1 These test methods cover the measurement of average
for the comparison method or simple templates for the manual
grain size and include the comparison procedure, the planim-
counting methods. Utilization of semi-automatic digitizing
etric (or Jeffries) procedure, and the intercept procedures.
tablets or automatic image analyzers to measure grain size is
These test methods may also be applied to nonmetallic
described in Test Methods E1382.
materialswithstructureshavingappearancessimilartothoseof
the metallic structures shown in the comparison charts. These
1.5 Thesetestmethodsdealonlywiththerecommendedtest
test methods apply chiefly to single phase grain structures but
methods and nothing in them should be construed as defining
theycanbeappliedtodeterminetheaveragesizeofaparticular
or establishing limits of acceptability or fitness of purpose of
type of grain structure in a multiphase or multiconstituent
the materials tested.
specimen.
1.6 The measured values are stated in SI units, which are
1.2 These test methods are used to determine the average
regarded as standard. Equivalent inch-pound values, when
grain size of specimens with a unimodal distribution of grain
listed, are in parentheses and may be approximate.
areas, diameters, or intercept lengths. These distributions are
1.7 This standard does not purport to address all of the
approximately log normal. These test methods do not cover
safety concerns, if any, associated with its use. It is the
methods to characterize the nature of these distributions.
responsibility of the user of this standard to establish appro-
Characterization of grain size in specimens with duplex grain
priate safety and health practices and determine the applica-
size distributions is described in Test Methods E1181. Mea-
bility of regulatory limitations prior to use.
surement of individual, very coarse grains in a fine grained
1.8 The paragraphs appear in the following order:
matrix is described in Test Methods E930.
Section Number
1.3 These test methods deal only with determination of
Scope 1
planar grain size, that is, characterization of the two-
Referenced Documents 2
Terminology 3
dimensional grain sections revealed by the sectioning plane.
Significance and Use 4
Determinationofspatialgrainsize,thatis,measurementofthe
Generalities of Application 5
sizeofthethree-dimensionalgrainsinthespecimenvolume,is
Sampling 6
Test Specimens 7
beyond the scope of these test methods.
Calibration 8
Preparation of Photomicrographs 9
1
Comparison Procedure 10
These test methods are under the jurisdiction of ASTM Committee E04 on
Planimetric (Jeffries) Procedure 11
Metallography and are the direct responsibility of Subcommittee E04.08 on Grain
General Intercept Procedures 12
Size.
Heyn Linear Intercept Procedure 13
Current edition approved Nov. 15, 2012. Published January 2013. Originally
Circular Intercept Procedures 14
approved in 1955. Last previous edition approved 2010 as E112–10. DOI:
Hilliard Single-Circle Procedure 14.2
10.1520/E0112-12.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E112 − 12
ing twin boundaries, the twin boundaries are ignored, that is,
Abrams Three-Circle Procedure 14.3
Statistical Analysis 15
the structure on either side of a twin boundary belongs to the
Specimens with Non-equiaxed Grain Shapes 16
grain.
Specimens Containing Two or More Phases or Constituents 17
Report 18
3.2.3 grain bounda
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E112 − 10 E112 − 12
Standard Test Methods for
1
Determining Average Grain Size
This standard is issued under the fixed designation E112; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
INTRODUCTION
These test methods of determination of average grain size in metallic materials are primarily
measuring procedures and, because of their purely geometric basis, are independent of the metal or
alloy concerned. In fact, the basic procedures may also be used for the estimation of average grain,
crystal, or cell size in nonmetallic materials. The comparison method may be used if the structure of
the material approaches the appearance of one of the standard comparison charts. The intercept and
planimetric methods are always applicable for determining average grain size. However, the
comparison charts cannot be used for measurement of individual grains.
1. Scope
1.1 These test methods cover the measurement of average grain size and include the comparison procedure, the planimetric (or
Jeffries) procedure, and the intercept procedures. These test methods may also be applied to nonmetallic materials with structures
having appearances similar to those of the metallic structures shown in the comparison charts. These test methods apply chiefly
to single phase grain structures but they can be applied to determine the average size of a particular type of grain structure in a
multiphase or multiconstituent specimen.
1.2 These test methods are used to determine the average grain size of specimens with a unimodal distribution of grain areas,
diameters, or intercept lengths. These distributions are approximately log normal. These test methods do not cover methods to
characterize the nature of these distributions. Characterization of grain size in specimens with duplex grain size distributions is
described in Test Methods E1181. Measurement of individual, very coarse grains in a fine grained matrix is described in Test
Methods E930.
1.3 These test methods deal only with determination of planar grain size, that is, characterization of the two-dimensional grain
sections revealed by the sectioning plane. Determination of spatial grain size, that is, measurement of the size of the
three-dimensional grains in the specimen volume, is beyond the scope of these test methods.
1.4 These test methods describe techniques performed manually using either a standard series of graded chart images for the
comparison method or simple templates for the manual counting methods. Utilization of semi-automatic digitizing tablets or
automatic image analyzers to measure grain size is described in Test Methods E1382.
1.5 These test methods deal only with the recommended test methods and nothing in them should be construed as defining or
establishing limits of acceptability or fitness of purpose of the materials tested.
1.6 The measured values are stated in SI units, which are regarded as standard. Equivalent inch-pound values, when listed, are
in parentheses and may be approximate.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.8 The paragraphs appear in the following order:
Section Number
Scope 1
1
These test methods are under the jurisdiction of ASTM Committee E04 on Metallography and are the direct responsibility of Subcommittee E04.08 on Grain Size.
Current edition approved Nov. 1, 2010Nov. 15, 2012. Published December 2010January 2013. Originally approved in 1955. Last previous edition approved 20042010 as
ε2
E112 – 96E112 – 10.(2004) . DOI: 10.1520/E0112-10.10.1520/E0112-12.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E112 − 12
Referenced Documents 2
Terminology 3
Significance and Use 4
Generalities of Application 5
Sampling 6
Test Specimens 7
Calibration 8
Preparation of Photomicrographs 9
Comparison Procedure 10
Planimetric (Jeffries) Procedure 11
General Intercept Procedures 12
Heyn Linear Intercept Procedure
...
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