This specification covers high magnesium marine application aluminum-alloy in those alloy tempers for flat sheet, coiled sheet, and plate, in the mill finish that are intended for marine and similar environments. An inspection lot shall consist of an identifiable quantity of material of the same mill form, alloy, temper, cast or melt lot, and thickness, subjected to inspection at one time. The material shall be supplied in the mill finish and shall be uniform as defined by the requirements of this specification and shall be commercially sound. Each coil, sheet and plate shall be examined to determine conformance to this specification with respect to general quality and identification marking. One sample shall be taken from each end of each parent coil, or parent plate. Alloy-tempers are manufactured and corrosion tested for intended use in marine hull construction or in marine applications where frequent or constant direct contact with seawater is expected. The specimen shall be capable of exhibiting resistance to intergranular corrosion as indicated by an acceptable mass-loss when tested and shall also be capable of exhibiting no evidence of exfoliation or corrosion. Under metallographic examination, the microstructure of a sample from each production lot shall be compared to that of the producer-established reference photomicrograph of acceptable material, in the same thickness range. Each shipping container shall be marked with the purchase order number, material size, specification number, alloy and temper, gross and net weights, and the producer's name or trademark.

1.1 This specification covers high magnesium aluminum-alloy products in the mill finish condition that are intended for marine hull construction and other marine applications where frequent or constant direct contact with seawater is expected and for similar environments (Note 1). Aluminum alloy products covered by this specification include the alloy-tempers of flat sheet, coiled sheet, and plate shown in Table 2 [Table 3] and Table 4 [Table 5], and alloy-tempers of extruded profiles shown in Table 6 [Table 7].

Note 1: There are other aluminum alloy-temper products that may be suitable for use in marine and similar environments, but which may not require the corrosion resistance testing specified by B928/B928M. See Specification B209 or B209M for other aluminum sheet and plate alloy-temper products. For other aluminum extruded alloy-temper products see Specification B221 or B221M and/or other relevant specifications for aluminum extruded products.

1.2 Alloy and temper designations are in accordance with ANSI H35.1/H35.1 (M). The equivalent Unified Numbering System alloy designations are those of Table 1 preceded by A9, for example, A95083 for 5083 in accordance with Practice E527.

1.3 The values stated in either SI units (Table 3 and Table 5) or inch-pound units (Table 2 and Table 4) are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of each other. Combining values from the two systems may result in non-conformance with the standard.

1.4 For acceptance criteria for inclusion of new aluminum and aluminum alloys in this specification, see Annex A2.

1.5 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.