Page 63: of Maritime Reporter Magazine (November 2003)

Marine Materials

Representatives of aluminum producers, boat builders and classification societies actively participated in the ASTM spec- ification development process, which in addition to electronic distribution and balloting, included two ASTM task group meetings held in conjunction with

ASTM committee weeks in November 2002 and May 2003.

Key elements of this new specification (ASTM B 928 "High Magnesium

Aluminum-Alloy Sheet & Plate for

Marine Service") are the requirements that the referenced materials be capable of meeting the corrosion requirements of both ASTM G 66 (Test Method for

Visual Assessment of Exfoliation

Corrosion Susceptibility of 5xxx Series

Aluminum Alloys (Asset Test)) and

ASTM G 67 (Test Method for

Determining the Susceptibility to

Intergranular Corrosion of 5xxx Series

Aluminum Alloys by Mass Loss After

Exposure to Nitric Acid (NAMLT

Test)). Another significant aspect of the specification is that the requirement applies to both the HI 16 and H321 tem- per designations for high magnesium aluminum alloys.

Concurrent with the ASTM activities, the Aluminum Association task group continued to meet to supply input on the draft specification as well as to address additional alloy-temper product registra- tions that will be included in future revi- sions to ASTM B 928. which are already underway. In addition The Aluminum

Association's Technical Committee on

Product Standards, which is the North

American registrar of alloy-temper product registrations, will restrict the assignment of the HI 16 and H321 tem- per designations to 5xxx alloys with a nominal magnesium content equal to or greater than 3% and which have the capability of meeting the corrosion requirements of both ASTM G66 and

ASTM G67. In the near future, the alloys and tempers covered by ASTM B 928 will be removed from ASTM B 209 making ASTM B 928 the sole ASTM material specification for Marine Sheet and Plate.

At this time, the introduction of this new material specification is for the information of aluminum end-users in

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