ASTM E930-99

Standard Test Methods for Estimating the Largest Grain Observed in a Metallographic Section (ALA Grain Size)

SCOPE
1.1 These test methods describe simple manual procedures for estimating the size of the largest grain observed on a metallographically prepared plane section.  
1.2 These test methods shall only be valid for microstructures containing outlier course grains, where their population is too sparse for grain size determination by Test Methods E112.
1.3 This standard does not purport to address all of the safety problems, 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.

General Information

• Status: Historical
• Publication Date: 09-Apr-1999
• ICS: 19.120 - Particle size analysis. Sieving
• Technical Committee: E04 - Metallography
• Drafting Committee: E04.08 - Grain Size

Relations

• Referred By: ASTM E1181-02(2023) - Standard Test Methods for Characterizing Duplex Grain Sizes
• Effective Date: 10-Apr-1999
• Referred By: ASTM E112-13(2021) - Standard Test Methods for Determining Average Grain Size
• Effective Date: 10-Apr-1999
• Referred By: ASTM E1382-97(2023) - Standard Test Methods for Determining Average Grain Size Using Semiautomatic and Automatic Image Analysis
• Effective Date: 10-Apr-1999
• Referred By: ASTM F799-19 - Standard Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Forgings for Surgical Implants (UNS R31537, R31538, R31539)
• Effective Date: 10-Apr-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E930–99
Standard Test Methods for
Estimating the Largest Grain Observed in a Metallographic
Section (ALA Grain Size)
This standard is issued under the fixed designation E 930; 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 (e) 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
Commercial material specifications sometimes include, in size limits for grain structures, the need
for identification of the largest grain observed in a sample, often expressed asALA(as large as) grain
size. The methods presented here are for use when the number of large grains is too few for
measurement by Test MethodsE112. It shall be understood that larger (but unobserved) grains may
exist in the local volume sampled.
1. Scope ALAGrain Size VisualAid for Comparison Procedure (One
Opaque Print and One Transparency)
1.1 These test methods describe simple manual procedures
for measuring the size of the largest grain cross-section
3. Terminology
observed on a metallographically prepared plane section.
3.1 Definitions:
1.2 These test methods shall only be valid for microstruc-
3.1.1 All terms used in these test methods are either defined
tures containing outlier coarse grains, where their population is
in TerminologyE7, or are discussed in 3.2.
too sparse for grain size determination by Test MethodsE112.
3.2 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.2.1 ALA grain, n—the largest grain observed in a random
safety problems, if any, associated with its use. It is the
scatterofindividualcoarsegrainscomprising5 %orlessofthe
responsibility of the user of this standard to establish appro-
specimen area, where the apparent grain size of these coarse
priate safety and health practices and determine the applica-
grains differs by 3 or moreASTM grain size numbers from the
bility of regulatory limitations prior to use.
balance of the microstructure.
3.2.2 outlier grain, n—a grain substantially different in size
2. Referenced Documents
from the predominant grain size in a microstructure; for
2.1 ASTM Standards:
example, an ALA grain.
E3 Methods of Preparation of Metallographic Specimens
E7 Terminology Relating to Metallography
4. Significance and Use
E112 Test Methods for Determining Average Grain
4.1 The presence of large grains has been correlated with
Size
anomalous mechanical behavior in, for example, crack initia-
E 407 Practice for Microetching Metals and Alloys
tion, crack propagation, and fatigue. Thus there is engineering
E 1181 Test Methods for Characterizing Duplex Grain
justification for reporting the ALA grain size.
Sizes
4.2 These methods shall only be used with the presence of
2.2 ASTM Adjuncts:
outlier coarse grains, 3 or more ASTM grain size numbers
largerthantherestofthemicrostructureandcomprising5 %or
less of the specimen area.Atypical example is shown inAnnex
This test method is under the jurisdiction of ASTM Committee E04 on
Metallography and is the direct responsibility of Subcommittee E04.08 on Grain
A1 as Fig. A1.1.
Size.
Current edition approved April 10, 1999. Published July 1999. Originally
e1
published as E 930 – 83. Last previous edition E 930 – 92 .
2 3
Annual Book of ASTM Standards, Vol 03.01. Available from ASTM Headquarters. Order Adjunct: ADJE0930.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E930–99
TABLE 1 Relationship of ALA Grain Area to ALA Micro-Grain
4.3 Thesemethodsshallnotbeusedforthedeterminationof
A
Size Number
average grain size, which is treated in Test Methods E112.
Area, mm Size
Examples of microstructures that do not qualify for ALA
2.06 00000 or − 4.0
treatment are shown in Annex A1 as Fig. A1.2, Fig. A1.3, and
1.46 −3.5
Fig. A1.4.
1.03 0000 or − 3.0
4.4 These methods may be applied in the characterization of
0.703 −2.5
duplex grain sizes, as instructed in the procedures for Test 0.516 000 or − 2.0
0.365 −1.5
Methods E 1181.
0.258 00 or − 1.0
0.182 −0.5
5. Sampling 0.129 0
0.0912 0.5
5.1 Sampling shall have been performed according to sam-
0.0645 1.0
pling procedures in Test MethodE112. 0.0456 1.5
0.0323 2.0
5.2 Thegenerallyintendedplaneofpolishisaplanepassing
0.0228 2.5
through the center of the thickness and exhibiting maximum
0.0161 3.0
grain aspect ratio. 0.0114 3.5
0.00807 4.0
5.3 Other polishing planes which may be more useful or
0.00570 4.5
predictive in specific products or applications are allowed.
0.00403 5.0
5.4 An unambiguous description of the plane of polish or a 0.00285 5.5
0.00202 6.0
reference to a description or drawing of the plane of polish
0.00143 6.5
shall be a part of the test report.
0.00101 7.0
5.5 Specimens shall be prepared in accordance with Meth-
A
Adapted from Test Methods E112, Table 2.
odsE3 and Practice E 407.
6.3.5 Compare this area with the grain areas in Table 1. Use
6. Procedures
the nearest area in the table to obtain the ALA grain size
6.1 In 6.2 a comparison procedure is presented with accu- number,unlessthenextsmallerorthenextlargerareaisagreed
racy near to 61ASTM grain size number, for the apparent size
upon between the interested parties.
of the largest grain. For greater accuracy, a measuring proce-
NOTE 2—Any automatic or semiautomatic measuring device which
dureisdescribedin6.3.Amanualquantitativemethod,toserve
provides the area of a grain section can also be used within the framework
as referee procedure, is described in 6.4. (The measuring
of this manual
...