ASTM A751-21

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: A751 − 20 A751 − 21
Standard Test Methods and Practices for
Chemical Analysis of Steel Products
This standard is issued under the fixed designation A751; 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 U.S. Department of Defense.
INTRODUCTION
These test methods and practices were prepared to answer the need for a single document that would
include all aspects of obtaining and reporting the chemical analysis of steel, stainless steel, and related
alloys. Such subjects as definitions of terms and product (check) analysis variations (tolerances)
required clarification. Requirements for sampling, meeting specified limits, and treatment of data
usually were not clearly established in product specifications.
It is intended that these test methods and practices will contain all requirements for the
determination of chemical composition of steel, stainless steel, or related alloys so that product
specifications will need contain only special modifications and exceptions.
1. Scope*
1.1 These test methods and practices cover definitions, reference methods, practices, and guides relating to the chemical analysis
of steel, stainless steel, and related alloys. They include both wet chemical and instrumental techniques.
1.2 Directions are provided for handling chemical requirements, product analyses, residual elements, and reference standards, and
for the treatment and reporting of chemical analysis data.
1.3 These test methods and practices apply only to those product standards which include these test methods and practices, or parts
thereof, as a requirement.
1.4 In cases of conflict, the product specification requirements shall take precedence over the requirements of these test methods
and practices.
1.5 Attention is directed to ISO/IEC 17025 when there may be a need for information on criteria for evaluation of testing
laboratories.
1.6 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
These test methods and practices are under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and are the direct responsibility of
Subcommittee A01.13 on Mechanical and Chemical Testing and Processing Methods of Steel Products and Processes.
Current edition approved Nov. 1, 2020Nov. 1, 2021. Published December 2020November 2021. Originally approved in 1977. Last previous edition approved in 20142020
as A751 – 14a.A751 – 20. DOI: 10.1520/A0751-20.10.1520/A0751-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A751 − 21
2. Referenced Documents
2.1 ASTM Standards:
A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E50 Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related Materials
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E322 Test Method for Analysis of Low-Alloy Steels and Cast Irons by Wavelength Dispersive X-Ray Fluorescence
Spectrometry (Withdrawn 2021)
E350 Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought
Iron
E352 Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium- and High-Alloy Steels
E353 Test Methods for Chemical Analysis of Stainless, Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-Iron
Alloys
E354 Test Methods for Chemical Analysis of High-Temperature, Electrical, Magnetic, and Other Similar Iron, Nickel, and
Cobalt Alloys
E415 Test Method for Analysis of Carbon and Low-Alloy Steel by Spark Atomic Emission Spectrometry
E548 Guide for General Criteria Used for Evaluating Laboratory Competence (Withdrawn 2002)
E572 Test Method for Analysis of Stainless and Alloy Steels by Wavelength Dispersive X-Ray Fluorescence Spectrometry
E743 Guide for Spectrochemical Laboratory Quality Assurance (Withdrawn 1998)
E851 Practice for Evaluation of Spectrochemical Laboratories (Withdrawn 1998)
E882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by
Various Combustion and Inert Gas Fusion Techniques
E1085 Test Method for Analysis of Low-Alloy Steels by Wavelength Dispersive X-Ray Fluorescence Spectrometry
E1086 Test Method for Analysis of Austenitic Stainless Steel by Spark Atomic Emission Spectrometry
E1097 Guide for Determination of Various Elements by Direct Current Plasma Atomic Emission Spectrometry
E1184 Practice for Determination of Elements by Graphite Furnace Atomic Absorption Spectrometry
E1282 Guide for Specifying the Chemical Compositions and Selecting Sampling Practices and Quantitative Analysis Methods
for Metals, Ores, and Related Materials
E1329 Practice for Verification and Use of Control Charts in Spectrochemical Analysis (Withdrawn 2019)
E1476 Guide for Metals Identification, Grade Verification, and Sorting
E1806 Practice for Sampling Steel and Iron for Determination of Chemical Composition
2.2 ISO Standards:
ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in these test methods and practices, see Terminology A941.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 product, check, or verification analysis, n—a chemical analysis of the semifinished or finished product, usually for the
purpose of determining conformance to the specification requirements.
3.2.1.1 Discussion—
The range of the specified composition applicable to product analysis is normally greater than that applicable to heat analysis in
order to take into account deviations associated with analytical reproducibility (Note 1) and the heterogeneity of the steel.
NOTE 1—All of the chemical analysis procedures referenced in these test methods include precision statements with reproducibility data, with the
exception of Test Methods E50.
3.2.2 product analysis tolerances, n—a permissible variation over the maximum limit or under the minimum limit of a specified
element and applicable only to product analyses, not cast or heat analyses (Note 2).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
A751 − 21
NOTE 2—The term “analysis tolerance” is often misunderstood. It does not apply to cast or heat analyses determined to show conformance to specified
chemical limits. It applies only to product analysis and becomes meaningful only when the heat analysis of an element falls close to one of the specified
limits. For example, stainless steel UNS 30400 limits for chromium are 18.00 to 20.00 %. A heat that the producer reported as 18.01 % chromium may
be found to show 17.80 % chromium by a user performing a product analysis. If the product analysis tolerance for such a chromium level is 0.20 %, the
product analysis of 17.80 % chromium would be acceptable. A product analysis of 17.79 % would not be acceptable.
3.2.3 proprietary analytical method, n—a non-standard analytical method, not published by ASTM, utilizing reference standards
traceable to the National Institute of Standards and Technology (NIST), when available, or other sources referenced in Section 10.
3.2.4 referee analysis, n—performed using ASTM test methods listed in 9.1.1, NIST reference standards or methods, and reference
standards agreed upon between parties.
3.2.4.1 Discussion—
The selection of a laboratory to perform the referee analysis shall be a matter of agreement between the supplier and the purchaser.
3.2.5 certified reference material, n—a specimen of material specially prepared, analyzed, and certified for chemical content under
the jurisdiction of a recognized standardizing agency or group, such as the NIST, for use by analytical laboratories as an accurate
basis for comparison.
3.2.5.1 Discussion—
Reference samples should bear sufficient resemblance to the material to be analyzed so that no significant differences are required
in procedures or corrections (for example, for interferences or inter-element effects).
3.2.6 working reference materials, n—reference materials used for routine analytical control and traceable to NIST standards and
other recognized standards when appropriate standards are available.
A751 − 21
4. Concerning Specification of Chemical Composition Requirements
4.1 It is recommended that Guide E1282 be consulted as a guide for specifying the chemical compositions for steels.
4.2 The recommended practice for specifying chemical composition limits is to limit the number of significant figures for each
element so that the number of figures to the right of the decimal point conforms to the following:
Maximum Number of
Chemical Concentration Figures to Right of Decimal Point
Up to 0.010 %, incl. 0.XXXX or may be expressed as ppm
Over 0.010 % to 0.10 %, incl 0.XXX
Over 0.10 % to 3.0 %, incl 0.XX
Over 3.0 % 0.X
4.3 For those cases in which the composition range spans either 0.10 or 3.0 %, the number of figures to the right of the decimal
is to be determined by that indicated by the upper limit.
4.4 Technical considerations may dictate the employment of less than the number of figures to the right of the decimal as
previously recommended.
NOTE 3—The recommendations should be employed to reduce the number of significant figures, such as from 18.00 to 18.0 %, but a significant figure
should never be added unless there is a technical reason for so doing.
5. Cast or Heat Analysis
5.1 The producer shall perform analyses for those elements specified in the material specification. The results of such analyses
shall conform to the requirements specified in the material specification.
5.1.1 For multiple heats, either individual heat or cast analysis, or an average heat or cast analysis, shall be reported. If significant
variations in heat or cast size are involved, a weighted average heat or cast analysis, based on the relative quantity of metal in each
heat or cast, shall be reported.
5.1.2 For consumable electrode remelted material, a heat is defined as all the ingots remelted by the same process from a primary
heat. The heat analysis shall be obtained from one remelted ingot, or the product of one remelted ingot, from each primary melt.
If this heat analysis does not meet the heat analysis requirements of the specification, one sample from the product of each remelted
ingot shall be analyzed, and the analyses shall meet the heat analysis requirements.
5.2 If the test samples taken for the heat analysis are lost, inadequate, or not representative of the heat, a product analysis of the
semifinished or finished product may be used to establish the heat analysis.
5.2.1 If a product analysis is made to establish the heat analysis, the product analysis shall meet the specified limits for heat
analysis and the product analysis tolerances described in Section 6 do not apply.
5.3 Unless otherwise specified, compositions shall be reported in mass fraction percent (wt%).
6. Product Analysis Requirements
6.1 For product analysis, the range of the specified chemical composition is normally greater (designated product analysis
tolerances) than that applicable to heat analyses to take into account deviations associated with analytical reproducibility
...