ASTM E1724-95

Standard Guide for Testing and Certification of Metal and Metal-Related Reference Materials

SCOPE
1.1 This guide describes procedures to be considered for the testing and certification of metal, ore, and metal-related reference materials in the form of blocks, disks, rods, wires, chips, and powders.
1.2 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.

General Information

• Status: Historical
• Publication Date: 31-Dec-1994
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials

Relations

• Replaced By: ASTM E1724-95(2001) - Standard Guide for Testing and Certification of Metal and Metal-Related Reference Materials (Withdrawn 2010)
• Effective Date: 01-Jan-1995

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1724 – 95
Standard Guide for
Testing and Certification of Metal and Metal-Related
Reference Materials
This standard is issued under the fixed designation E 1724; 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.
1. Scope Alloys for Spectrochemical Analysis
E 826 Practice for Testing Homogeneity of Materials for the
1.1 This guide describes procedures to be considered for the
Development of Reference Materials
testing and certification of metal and metal-related reference
E 877 Practice for Sampling and Sample Preparation of Iron
materials in the form of blocks, disks, rods, wires, chips, and
Ores and Related Materials
powders.
E 1019 Test Method for Determination of Carbon, Sulfur,
1.2 This standard does not purport to address all of the
Nitrogen, and Oxygen in Steel and Iron
safety concerns, if any, associated with its use. It is the
2.2 ISO Standards:
responsibility of the user of this standard to establish appro-
ISO Guide 30 Terms and Definitions Used in Connection
priate safety and health practices and determine the applica-
With Reference Materials
bility of regulatory limitations prior to use.
ISO Guide 31 Contents of Certificates of Reference Mate-
2. Referenced Documents rials
ISO Guide 33 Uses of Certified Reference Materials
2.1 ASTM Standards:
ISO Guide 35 Certification of Reference Materials—
E 32 Practices for Sampling Ferroalloys and Steel Additives
General and Statistical Principles
for Determination of Chemical Composition
E 34 Test Methods for Chemical Analysis of Aluminum and
3. Terminology
Aluminum-Base Alloys
3.1 Definitions—For definitions of terms used in this guide,
E 50 Practices for Apparatus, Reagents, and Safety Precau-
2 refer to Terminology E 135.
tions for Chemical Analysis of Metals
3.2 Definitions of Terms Specific to This Standard:
E 55 Practice for Sampling Wrought Nonferrous Metals and
3.2.1 certification report—a document giving detailed in-
Alloys for Determination of Chemical Composition
formation, supplementary to that contained in a certificate, on
E 59 Practice for Sampling Steel and Iron for Determination
the preparation of the material and the methods of measure-
of Chemical Composition
ment used in obtaining the certified value(s) for a given
E 88 Practice for Sampling Nonferrous Metals and Alloys
reference material. It includes a summary of the results
in Cast Form for Determination of Chemical Composition
obtained (including a description of all factors affecting accu-
E 135 Terminology Relating to Analytical Chemistry for
racy) and a description of the way in which the results were
Metals, Ores, and Related Materials
treated statistically.
E 178 Practice for Dealing with Outlying Observations
3.2.2 certified reference material (CRM)—reference mate-
E 255 Practice for Sampling Copper and Copper Alloys for
2 rial accompanied by a certificate, one or more of whose
the Determination of Chemical Composition
property values are certified by a procedure which establishes
E 350 Test Methods for Chemical Analysis of Carbon Steel,
its traceability to an accurate realization of the unit in which the
Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and
property values are expressed; each certified value is accom-
Wrought Iron
panied by an uncertainty at a stated level of confidence (from
E 351 Test Methods for Chemical Analysis of Cast Iron—
ISO Guide 30).
All Types
3.2.3 certifying body—a technically competent body (orga-
E 691 Practice for Conducting an Interlaboratory Study to
nization or firm, public or private) that issues a reference
Determine the Precision of a Test Method
material certificate which provides the information detailed in
E 716 Practices for Sampling Aluminum and Aluminum
ISO Guide 31.
3.2.4 comparative analytical method—an analytical proce-
This guide is under the jurisdiction of ASTM Committee E-1 on Analytical
dure that requires the use of CRMs, reference materials (RMs),
Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
Subcommittee E01.21 on Reference Materials and Liaison with S17.
Current edition approved Aug. 15, 1995. Published October 1995. Annual Book of ASTM Standards, Vol 03.06.
2 5
Annual Book of ASTM Standards, Vol 03.05. Available from American National Standards Institute, 11 West 42nd St., 13th
Annual Book of ASTM Standards, Vol 14.02. Floor, New York, NY 10036.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1724
or, in certain instances, primary chemical standards for cali- only a limited portion of a user’s range of interest.
bration. Methods vary widely in the number of such CRMs 4.3 When comparative analytical methods are employed,
required and the degree to which such CRMs must match appropriate CRMs are often unavailable for calibration. In this
unknown samples. case, the use of RMs is indicated as the alternative choice.
3.2.5 definitive analytical method—an analytical procedure 4.4 The use of uncertified homogeneous materials is appro-
that does not require the use of CRMs, RMs, or primary priate for control chart programs where relative data consis-
chemical standards to achieve accurate results. Examples tency is being monitored. The use of CRMs for such purposes
include gravimetry, coulometry, specific titrimetric methods, is often a misuse of valuable CRM stocks, especially when
and isotope dilution mass spectrometry. Each individual labo- uncertified materials of suitable homogeneity are available. For
ratory should validate its performance of such methods with information on the use and misuse of CRMs, see ISO Guide 33
CRMs, RMs, or primary chemical standards. and NBS Special Publication 260-100.
3.2.6 method of demonstrated accuracy—a test method for 4.5 Use CRMs and RMs with caution in the validation of
which proof of accuracy has been published, even though it analytical methods. The danger involves a potential for unde-
may not fall within the category of a reference method. tected systematic error, since the same methodology being
3.2.7 primary chemical standard—a pure metal or a com- validated may have been used to establish the values for the
pound of sufficient high purity to permit its use in the CRMs or RMs. For more information on the use of CRMs in
calibration or validation of analytical methods. the validation of analytical methods, see NIST Special Publi-
3.2.8 reference material (RM)—a material or substance, one cation 829.
or more of whose property values are sufficiently homogeneous
5. Hazards
and well established to be used for the calibration of an
apparatus, the assessment of a measurement method, or for 5.1 The preparation of reference materials involves hazards
assigning values to materials. associated with the melting, annealing, casting, sampling,
3.2.9 reference material certificate—a document stating one forging, rolling, atomizing, pickling, shot blasting, and ma-
or more property values and their uncertainties and confirming chining of metal. Similarly, hazards are encountered in crush-
that the necessary procedures have been carried out to establish ing, grinding, and sieving particulate and powdered materials.
their validity and traceability. A reference material certificate is 5.2 For precautions related to the analysis of reference
an essential attribute of CRM. materials, see Practices E 50.
3.2.10 reference method—a thoroughly investigated
6. Justification of Production
method, clearly and exactly describing the necessary condi-
tions and procedures for the measurement of one or more 6.1 Reference materials are needed to calibrate, verify, and
control instrument methods when sufficient certified reference
property values that has been shown to have accuracy and
precision commensurate with its intended use and can be used materials of the required composition or form, or both, are not
available from certifying bodies.
to assess the accuracy of other methods for the same measure-
ment, particularly in permitting the characterization of an RM. 6.2 Alloy types or grades not available from any certifying
body are often needed to match the composition to be tested.
This includes all national or international standard methods,
which may not be classified as definitive methods because they 6.3 A study should be made to estimate the cost of RM
production and testing. It is important that users remain aware
are calibrated against standard solutions of pure chemical
substances. that the preparation of RMs has an associated cost based on
factors such as material cost, facility usage charges, personnel
3.2.11 traceability—property of a result of a measurement
labor rates, outside laboratory fees, and so forth, in which the
whereby it can be related, with stated uncertainty, to stated
references, usually national or international standards, through material cost is, in general, the lowest. For complex composi-
tions, the cost of preparing RMs to match the composition of
an unbroken chain of comparisons (ISO Guide 30).
3.2.12 uncertainty of a certified value—the range of values test samples can exceed that of available CRMs. In these cases,
the use of CRMs is recommended.
within which the “true” value is asserted to lie with a stated
confidence. 6.4 A study of the costs associated with the RM production
should take into account the amount of usable material
3.2.13 validation (of an analytical method)—evidence that
a method yields accurate results on a test sample because it compared to the total amount produced. It may be necessary to
produce twice as much raw material in order to obtain the
yields accurate results on a CRM of similar composition which
was analyzed at the same time. target amount of usable RM.
4. Significance and Use
7. Types of Reference Materials and Reference Material
Forms Covered in This Guide
4.1 This guide describes the suggested procedures for the
preparation, testing, and certification of reference materials
7.1 Reference Materials:
(RMs) to be used in the calibration, verification, and control of
methods used to characterize the chemical composition of
NIST Special Publication 260-100, Handbook for SRM Users (1993 ed.).
metals, ores, and related materials.
Available from NIST, U.S. Department of Commerce, Gaithersburg, MD 20899.
4.2 Certified reference materials are frequently rare and
NIST Special Publication 829, Use of NIST Standard Reference Materials for
valuable commodities requiring investment of considerable
Decisions on Performance of Analytical Chemical Methods and Laboratories.
cost and production time. They are frequently available for Available from NIST.
E 1724
7.1.1 Multielement Reference Material—Certified for a 9. Production to Final Form
complete composition (may or may not include trace element
9.1 This guide will not specify the procedures used for
composition).
melting or production of the RM into the final form. Methods
7.1.1.1 Grade-Specific Reference Material—Meets or is
will vary in accordance with composition requirements.
close to the compositional specification for all elements of a
9.2 Some portions of the candidate material may need to be
particular grade of material.
discarded if homogeneity testing indicates the material is not
7.1.1.2 Drift-Correction Reference Material—A cast or
uniform.
wrought material evaluated for an array of elements, useful for
10. Sample Identification and Recordkeeping
drift correction of instrumental methods. A drift-correction RM
may conform to a compositional specification.
10.1 Material identification is required at all times during
7.1.2 Element-Specific Reference Material—Certified for a
RM production, especially during random sampling for the
small number of elements. A common type of element-specific
homogeneity testing. Proper sample identification will ensure
RM consists of chips or pins certified for carbon, sulfur,
that unacceptable portions of a candidate material may be
nitrogen, oxygen, or hydrogen, or a combination thereof.
isolated from the usable portion.
7.2 Reference Material Forms:
10.2 Proper recordkeeping is vital during the entire process
7.2.1 Monolithic Solids:
of the RM production, from the initial determination of the
7.2.1.1 Castings,
need to produce an RM, to the preparation of the analysis
7.2.1.2 Wrought material finished to bar form, and
report.
7.2.1.3 Rod and wire material.
11. Homogeneity Check
7.2.2 Particulates:
7.2.2.1 Chips, and 11.1 Estimate the amount of acceptable inhomogeneity prior
7.2.2.2 Powders. to the production of the material. The homogeneity testing
procedure shall be designed to test at least the minimum
NOTE 1—In many cases, full composition data, although not necessarily
sample size or test area required for its intended use.
certified, will be needed to permit corrections for interferences in various
11.2 Homogeneity testing is a crucial part of RM evalua-
instrumental methods, especially for critical elements at low concentra-
tion. Costs can be held to a minimum if a preliminary
tions.
homogeneity test, as described in Practice E 826, is performed
8. Specifications for the Finished Reference Material
before expensive fabrication and extensive testing is under-
8.1 If a composition is to be made by a melting process, a
taken. It may be necessary to design special test methods to
realistic approach should be taken when determining the
evaluate homogeneity of the bulk material prior to beginning
number of elements and their concentrations in each RM. If a
serial production methods such as ingot to bar, billet to bar, and
composition is to be made by a melting process, a detailed
bar to chips.
understanding of the metallurgical interactions between the
11.3 Perform the homogeneity test on the candidate material
added constituents and the matrix metal is necessary. In most
after it is produced to its final form and all physically
cases, the more elements specified, the greater the difficulty in
unacceptable portions (containing visible inclusions, “pipe,”
achieving the specification. Even the creation of a single
scale, and so forth) have been discarded.
element RM, such as sodium in an aluminum matrix, may be
11.4 A test for trend inhomogeneity should be done before
very difficult to produce.
random inhomogeneity is evaluated. The samples, however
8.2 The finished composition may be available in semi-
randomly selected, must keep traceability to their original
finished form, such as an ingot or a larger-than-specified bar or
location to avoid lo
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