Work Item
ASTM WK89024
Revision of A751-21 Standard Test Methods and Practices for Chemical Analysis of Steel Products
Rationale
This revision was originally proposed for A961, but several members of the A01.22 subcommittee thought it was better suited to A751 since A751 is invoked by numerous A01 product specifications, or their general requirements specifications. While many of those specifications provide guidance for the retesting of mechanical properties, retesting of a heat analysis chemistry that does not meet specification requirements is not addressed. For example, section 11.5 of the current edition of A961 requires that the tensile properties be retested two times when the original test does not meet requirements; both retests must pass. Section 12.4 requires two retests of the impact energy when one of the original specimens does not meet requirements; again, both retests must pass. This ballot extends similar retest restrictions to the heat analysis: the same limit on the number of retests and the same requirement that both retests must meet specification limits, which would prevent a lab from just retesting until a passing result is obtained. There is a precedent for guidance in re-analysis of chemistry in the rules for testing of materials used in the ship building industry and government procurement specifications, such as Federal Standard 151. The current silence in A751 for heat analysis retesting could be interpreted as allowing users to define their own rules for the number of permitted retests, leading to a variety of retest practices. The need for a retest in some cases is reasonable considering a bath chemistry that is at the limit of a specified range when tested in process as a ladle sample may analyze slightly differently and be out of specification when tested and reported from the casting stream, when no further alloying or refining is possible.
This ballot allows retesting of the original heat analysis sample because in the case of reporting the heat analysis from samples taken from the casting stream, which is common practice, no further sampling is possible after the heat is finished casting.
The proposed change would be an additon of a section 5.4 stating: If the results of the heat analysis do not conform to the requirements specified in the product specification, the original sample may be re-analyzed two additional times. When either re-analysis does not conform to the product specification requirements, the lot represented by that sample shall be rejected.
Work Item Status
Date Initiated: 12-19-2023
Technical Contact: William Page