Table 4-7. Identification of Magnesium Alloys - CONT
Castings - continued
HTA- I (Heat-Treated
and Partially Aged)
and Fully Aged)
DOW-Dow Chemical Company
2 ASTM-American Society for Testing Materials
AMC-American Magnesium Corporation
(c) Tubing. Mark the following information at 2-foot intervals along tubing.
Federal Specification WW-T-825 or manufacturer s alloy number.
Manufacturer's name or trademark.
(d) Castings. Castings should be marked by the manufacturer with pattern number or part number. Marking
should be accomplished by a molded, raised symbol.
(e) All forms. Magnesium alloys that cannot be marked as specified in steps (a) through (d) above should
have the required information placed on cloth or metal tags and securely fastened to each bundle.
Testing. Use a spot test to distinguish magnesium, with no identification markings, from aluminum. Spot test is
accomplished as follows:
(1) Clean unknown alloy with a file, removing all paint or other surface coating to expose base metal.
(2) Place a drop of one-half of 1 percent solution of silver nitrate, MIL-W-535, on cleared surface. The
metal is magnesium when surface tested turns black. When no reaction occurs, metal is probably aluminum.
Cadmium and zinc also react to silver nitrate, but these metals are in thin coatings, and
should be removed by filing performed in step (1) above.
Storage. Storage treatment, procedures, and precautions are explained in the paragraphs below.
(1) Treatment. Apply chrome-pickle solution to magnesium alloys in accordance with MIL-M-3171 as a
protection against corrosion.
(2) Procedure. Store magnesium alloys in racks or bins in a cool, well-ventilated area away from fire hazards,
open flames, oxidizing agents, or heat sources.
Do not use water or any standard liquid or foam-type fire extinguishers; an explosion