ASTM-A480/A480M:2020 pdf free download – Standard Specification for General Requirements for Flat-Rolled Stainless and Heat- Resisting Steel Plate, Sheet, and Strip.
6.2.4 The purchaser is permitted to make the requirements for any element more stringent; that is. require higher minimums for elements having minimum requirements or ranges with minimum requirements, or requiring lower maximums for elements having specified maximums, or ranges with maximums. The purchaser is not permitted to make chemical requirements less stringent.
6.2.5 Analysis limits shall be established for specific elements rather than groups of elements, including but not limited to all others, rare earths, and balance, unless all elements in such a group are similar in technical effect and are associated in typical methods of chemical analysis.
6.3 Except as permitted in 6.3.1, the steel shall not contain an unspecified element for the ordered grade to the extent that the steel conforms to the requirements of another grade for which that element is a specified element having a required minimum content. For this requirement, a grade is defined as an alloy described individually and identified by its own UNS designation in a table of chemical requirements within this specification or any specification listed within the scope as being covered by the specification.
6.3.1 Unless otherwise specified to lower maximum limits on the purchase order, maximum allowances for unspecified elements will be established for Cu. Mo. Ti, and Nb for the specified grade if the amount of that element present in the material conforms with composition limits for that element in another grade. These allowances are Cu, 0.75 %; Mo. 0.75 %; Ti. 0.10%; and Nb, 0.10%.
6.3.2 If any allowance in 6.3.1 is used to demonstrate non-substitution, then the element involved shall be reported as if it were a specified element.
6.4 The producer is not permitted to certify that material is in compliance with an ASTM product specification when the purchase order has required that the material contain as a minimum or range an element that is neither a specified element nor an intentionally added unspecified element for the ordered grade in accordance with the definitions of Test Methods, Practices, and Terminology A751.
6.5 The names Columbium (Cb) and Niobium (Nb) both refer to element 41. The name Niobium is pretBrred, but either is acceptable for reporting composition.
7. Product Analysis
7. 1 The purchaser is permitted to pertorm a product analysis (formerly check analysis) to verify the identity of the finished material representing each heat or lot. Such analysis shall he made by any of the commonly accepted methods that will positively identify the material.
7.2 The chemical composition determined in accordance with 7.1 shall conform to the limits of the material specification within the tolerances of Table A 1.1, unless otherwise specified in the applicable material specification or the purchase order. The allowable variation of a particular element in a single sample for product analysis is permitted to be either above or below the specified range. However, percentages must exhibit the same tendencies in all samples; that is, the several determinations of any individual element in a heat shall not vary both above and below the specified range.