Table 6-2.—Aluminum Alloy Tubing Applications Old Specification WW-T-383 WW-T-787 WW-T-789 New Specification WW-T-700/1 WW-T-700/4 WW-T-700/6 Type 1100 - 0 -H12 -H14 -H16 -H18 5052 - 0 -H32 -H34 -H36 -H38 6061 -   0 - T4 - T61 General Usage and Applications Tubing conforming to Federal Specification WW-T-700/1 shall not be used in hydraulic systems. Specification covers tempers from annealed to full-hard. Used mostly in O-annealed condition. Good formability. Used where high strength is not necessary, as in low- or negative-pressure (nonhydraulic) lines. Specification covers tempers from annealed to full-hard. Used mostly in O-annealed condition. Has good workability. Used in medium-pressure systems (1500 psi max.) Specification covers annealed and three heat-treated tempers. Used mostly in O-annealed and T-6. Has good workability. Tubing conforming to Federal Specification WW-T-700/6 shall not be used in hydraulic systems. ¹0nly 6061-T6 is of sufficient strength to use in the repair of aluminum tubing systems. In an emergency, the other alloys of aluminum maybe used with AN fittings to make temporary repairs only. Table 6-3.—AN/MS Tube Fitting Color Codes MATERIAL OR FINISH COLOR Aluminum Alloy Blue Carbon Steel Black Corrosion Resistant Steel Natural Aluminum-bronze Cadmium Plate Titanium Natural to Grey, Depending on Type and Intended Use. 6-3