ASTM A751:20 pdf download

ASTM A751:20 pdf download.Standard Test Methods and Practices for Chemical Analysis of Steel Products.
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 I) and the heterogeneity of the steel.
NOTE 1—All of the chemical analysis procedures referenced in these test methxls include precision stawments 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).
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 clement falls close to one of the specified limits. For example, stainless steel (iNS 304(X) 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 refrree anal vsis, 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.